[mazez]

I have done extensive research and cannot find a definitive answer to this question, and its been on my mind for a while now. Would an e90 330i with m3 spec coil-overs, thicker sway bars, strut bar, control arms, bushings, tie rods, tension struts, wishbones, trailing arms, rear chasis A brace etc basically a full suspension refresh, handle like an M3? Wheels/tires, and steering rack also will obviously make a big difference. Is there anyone that has driven a full suspension non M and then hopped into an m3? How do they compare, besides the fact the steering feel will be different. The reason I ask is I've been deciphering between another 330(R.I.P.) or an M3 but nothing in between, no hate on the n54 its one hell of an engine. The enormous difference in price would leave me with a lot of mod money. I only care about the handling in terms of this question, every other category including the engine, exterior, and interior, can be taken care of custom so please no off topic answers. All replies extremely appreciated.
Thanks
-Former and soon to be another E90 owner

[tlow98]

I don't see why it wouldn't. To be fully correct you'd need to do king pins and, brakes and springs/dampers. Then you'd be very close. Front subframe is differnet, but splitting hits then.

Also, 335 vs 328 only a few thousand diff these days.

[floydarogers]

Originally Posted by mazez

I have done extensive research and cannot find a definitive answer to this question, and its been on my mind for a while now. Would an e90 330i with m3 spec coil-overs, thicker sway bars, strut bar, control arms, bushings, tie rods, tension struts, wishbones, trailing arms, rear chasis A brace etc basically a full suspension refresh, handle like an M3? Wheels/tires, and steering rack also will obviously make a big difference....

The M3 suspension results in a wider stance. You have to make body (fender) changes to get the tires (any tires) to fit.

[tlow98]

No, that's not true. You can run narrower wheels with a higher offset. You can also run increased camber. There are lost of options.

The wider stance of the M is mostly due to lower offset wheels that are wider.

[floydarogers]

Originally Posted by tlow98

No, that's not true. You can run narrower wheels with a higher offset. You can also run increased camber. There are lost of options.

The wider stance of the M is mostly due to lower offset wheels that are wider.

Pretty sure the wheel hubs are out further... But I haven't measured it so you might be right.

[BMDoublYou]

At this point one must question whether just buying an m3 and calling it a day is the sound financial decision, not to mention that glorious v8!

[Nguyenhu0106]

I personally own a modded e90 335i and driven a e90 m3.

my personal opinion, at the end of the day i think it would be cheaper and a hell of a lot less work of you get the M3...
the m3 reacts to turns faster.. brakes are better, and you get that V8. Also now is the time to by anything that has a v8, m3, isf, s5.. the m3 specificlly hasn't really been dropping much any more.

but before you go out and get a m3.. there are alot of things to consider.
since you are coming from a 330i there are alot more expenses that you didn't have on the 330i.

obviously gas will hurt but maintenance.

Rod bearings.
ive seen people change these out proactively or forced when they start hearing knocking and or chattering. no matter how you drive, these will wear out eventually because of the nature of the motor. this job will usually cost 2500 to 3000 from what i see.
People have reported wear anywhere from 6000 miles to anywhere after.

throttle actuators
there are two of them, one for each bank.
there are plastic gears inside that will grind down over time when the throttle bodies start to dry out and they get harder to open and close. this will grind down the plastic gears and eventually need to be replaced. they cost 1000 per actuator.
this can be prevented if you regularly lube the individual throttle bodies.

here is a video of a guy explaining the cost and at the end he was eventually forced to sell the car because is $70,000 a year job wasn't enough to maintain the car and save for his future.

i hope this helps with your decisions

[Torgus]

buy either and a tuned n54 will still be faster.

Why are you so concerned about the suspension out of curiosity?

If you think parts for a bmw are expensive have fun with the m3...also just go aftermarket suspension on either.

[tlow98]

Originally Posted by floydarogers

Pretty sure the wheel hubs are out further... But I haven't measured it so you might be right.

The hubs are farther, but from what I researched, not enough to really matter.

The numbers lay out as follows.

Track width 328i F/R
59.3 / 59.6

M3 F/R
60.6 / 60.6

Difference of F/R
1.3" / 1.0"

Difference per side
.65" FL/FR - 16.5mm + difference in tire width (25mm/2) = ~29mm
.5" RL/RR - 12.5mm + difference in tire width (35mm/2) = ~30mm

Now given that a 328i can run 20mm spacer up front it stands to reason that it should accommodate the M3 running with camber (-1.5ish is plenty) and a correctly spec'd wheel (35ish ET). Also, I've heard but not measured that the front subframe of the M3 is actually 5mm narrower than the standard 3er. Haven't been able to verify this.

The rear is a similar story, but with more room, so it should be easier.

Not trying to be a know-it-all by any means. I did all this research for my swap project that I've since shelved. Hope someone else finds it useful and if you have anything to add, please do!

In the end the wider fender flares of the M are very functional given the factory tolerances and the ability to run huge stuff on the stock M, but it seems from my research the stock M stuff is relatively conservative.

Of course, you're not going to be able to huge width tires without going wider on the bodywork, but huge rubber likely isn't needed given the power output.

[tlow98]

Originally Posted by BMDoublYou

At this point one must question whether just buying an m3 and calling it a day is the sound financial decision, not to mention that glorious v8!

Average M3 is about 2.5x the cost of a 328i (m3;328 $30k;$12k). If sourced smartly, one could have all the stock M3 suspension stuff for a few grand.

I guess it's a personal decision if the bodywork/interior/motor/trans of the m3 is worth the extra $15k. Piece by piece this stuff is still worth more than 15k according to second hand prices, so one could make the argument for the M3 being a relative bargain. But if you only want part of what an M3 is, then you are paying more than is necessary to attain your goal buy buying an M3.

If all that 'other' stuff is overkill for the OP, then he wouldn't want it nor would he want to pay for it.

I've owned a few M3s and now the E91, but I have to say I'd love to have the handling of the M3 more than almost anything. E91 space/reliability/efficiency with M3 moves...that peaks my interest, personally.

It's all subjective.

[mazez]

I think I'm gonna go with the 330 for the purpose and satisfaction of being able to extensively modify for the next 2 years vs car payment, higher insurance, much more maintenance only leaves little for mod money until studies are finished and I can go all out. Ill probably drive an m3 2 years from now and turn this into a full in project car.

[BMDoublYou]

Originally Posted by tlow98

Average M3 is about 2.5x the cost of a 328i (m3;328 $30k;$12k). If sourced smartly, one could have all the stock M3 suspension stuff for a few grand.

I guess it's a personal decision if the bodywork/interior/motor/trans of the m3 is worth the extra $15k. Piece by piece this stuff is still worth more than 15k according to second hand prices, so one could make the argument for the M3 being a relative bargain. But if you only want part of what an M3 is, then you are paying more than is necessary to attain your goal buy buying an M3.

If all that 'other' stuff is overkill for the OP, then he wouldn't want it nor would he want to pay for it.

I've owned a few M3s and now the E91, but I have to say I'd love to have the handling of the M3 more than almost anything. E91 space/reliability/efficiency with M3 moves...that peaks my interest, personally.

It's all subjective.

You forgot the cost of labor, and the downtime with the car that will require a second vehicle. At that point sourcing a donor m3 car would be your best bet just so you know you have all the nuts and bolts you need to do it right! And all this for what? a coupe/sedan that already exists, minus about 200hp.

As you said, it's all subjective. everyone gets to make their choices, I would support you if you decided to pick up an m3 donor car and slap the suspension into your e91, now that's a project I would love to do myself one day

[Torgus]

And I'm out.

[Nguyenhu0106]

if money does not matter.. i would go m3.. it is possible to bolt everything on.. but there are alot of parts to covert the non-m to the m3...
the front alone requires hood, fenders, headlights, bumper just to fit the front suspension in. then the back.. the rear fenders are flared.. not sure if you are going to do the bolted fender flares but if you want the m3 rear fenders.. it would require cut and weld and repaint, then the rear bumper.
after all that, a you would require an alignment just to make sure all is well.

somewhere in the forums.. there was a foreign guy converted his non-m to look like a M.. the car ended up costing more than an m3.

yes everything would bolt on.. you would pretty much need a wrecked m3 for the suspension bits and subframe and brakes.

but if it was my money i would just get the M3, since it's a project car.. you would at least have fun with the v8 in the meantime and not worry and waste time converting it to the m3. you are already there half the fight is done.

[tlow98]

Originally Posted by BMDoublYou

You forgot the cost of labor, and the downtime with the car that will require a second vehicle. At that point sourcing a donor m3 car would be your best bet just so you know you have all the nuts and bolts you need to do it right! And all this for what? a coupe/sedan that already exists, minus about 200hp.

As you said, it's all subjective. everyone gets to make their choices, I would support you if you decided to pick up an m3 donor car and slap the suspension into your e91, now that's a project I would love to do myself one day

Good points on install costs and second vehicle. I almost always assume people do things themselves on forums, which is not always the case.