[Dutt1113]

I know this is a BMW forum, but hoping for some open minded options. Any thoughts or experience with both cars? I know they are not direct competitors, but they are both fast 4wd cars. Can't decide between a low mileage high spec 18' m550i vs 18' RS5 coupe. I say coupe because I would like the RS5 SB, but it's too new on used market and more than I want to spend. I don't require 4 doors, have just 2 people 99% of the time, or I'd just take our other SUV for more space if needed. I thought maybe an S5 SB. I test drove one once and although quick, it didn't excite me and had turbo lag or transmission lag or something. I could piggy back ecu and tune TCM to about 420hp and fix the lag, but wondered if I should have got an RS car hence the coupe although less practical. The RS5 con is lack of heated steering and no leather/stitched look dash on a $85k MSRP luxury coupe which is borderline pathetic. Build quality they say is good all around. The m550i has more luxury features and materials throughout with leather dash/door tops, etc but lacks the sweet virtual cockpit and looks/prestige of rs5.

[jsf721]

I looked at Audi and BMW. Choose BMW bc it seemed the service on the Audi was nuts and they are more delicate and I’m rough on cars.

[SteveinArizona]

As you note, two completely different cars. The Audi is smaller and more nimble (sort of but remember that it is front wheel biased) but the BMW is faster, roomier, and more luxurious.

Depends upon your needs and desires. They are both good cars and as with all cars, there are plusses and minuses to each.

[SXY550]

Originally Posted by Dutt1113

I know this is a BMW forum, but hoping for some open minded options. Any thoughts or experience with both cars? I know they are not direct competitors, but they are both fast 4wd cars. Can't decide between a low mileage high spec 18' m550i vs 18' RS5 coupe. I say coupe because I would like the RS5 SB, but it's too new on used market and more than I want to spend. I don't require 4 doors, have just 2 people 99% of the time, or I'd just take our other SUV for more space if needed. I thought maybe an S5 SB. I test drove one once and although quick, it didn't excite me and had turbo lag or transmission lag or something. I could piggy back ecu and tune TCM to about 420hp and fix the lag, but wondered if I should have got an RS car hence the coupe although less practical. The RS5 con is lack of heated steering and no leather/stitched look dash on a $85k MSRP luxury coupe which is borderline pathetic. Build quality they say is good all around. The m550i has more luxury features and materials throughout with leather dash/door tops, etc but lacks the sweet virtual cockpit and looks/prestige of rs5.

Was faced with the same dilemma. Test drove both cars. Liked Audi's dashboard but hated the V6, the wet-towel-over-exhaust sound, and shit handling. For m550i I loved the V8 power, luxury(the 5 series seats are just so comfortable), sound(with resonators cut of course), handling, and ability to power slide(someone asked me if my m550 was rear wheel drive haha). I came from a coupe(f type) as well but m550i's handling is no worse than the f type. Once you go V8 you never go back man.

[jjscsix]

My only problem with buying a used M550 is that I would always be pissed off that I didn’t get the new 523 HP version. Otherwise I’d say go with the M550. I like the Audi’s a lot, I had two A7s, but given your choices I just like the 5 series better.

BTW, I am a fan of the Audi 5’s but only at a lower price point.

[Dseverson]

I test drove both 2018 RS5 sport back and 2018 M550i. The RS seems to have more turbo lag, the M a bit less. I wasn't completely inspired by the Audi although the tech was a bit better. The m550 is quick and super smooth. I don't regret buying the M550i one bit!

[Dutt1113]

Originally Posted by jjscsix

My only problem with buying a used M550 is that I would always be pissed off that I didn’t get the new 523 HP version. Otherwise I’d say go with the M550. I like the Audi’s a lot, I had two A7s, but given your choices I just like the 5 series better.

BTW, I am a fan of the Audi 5’s but only at a lower price point.

from what I understand, the '18/19 m550's were dyno'd to have BMW's advertised HP of 462ish at the wheels so they would already have over 500hp at the crank which is what BMW now advertises for the 2020. Sure, they made some "updates" for the 2020 engine (n63tu3) to give the impression of more power. It probably does have a little more power, but i feel like it was all marketing in the beginning (whp) to give some room for the m5 to shine when it came out. Now, for 2020 bmw can advertise crank hp.

[jjscsix]

Originally Posted by Dutt1113

from what I understand, the '18/19 m550's were dyno'd to have BMW's advertised HP of 462ish at the wheels so they would already have over 500hp at the crank which is what BMW now advertises for the 2020. Sure, they made some "updates" for the 2020 engine (n63tu3) to give the impression of more power. It probably does have a little more power, but i feel like it was all marketing in the beginning (whp) to give some room for the m5 to shine when it came out. Now, for 2020 bmw can advertise crank hp.

I've seen credible road tests of M850s which should have performance basically the same as a 2020 M550. There is no doubt that it really does have at least 75 more HP. The numbers are there. BMW has always gotten more out of their HP than almost any other mfr.

And the 550 does not have to be tweaked to make the M5 look better. Motor Trend dyno'd an M5 at 600 at the wheels. And I've seen credible tests on them at10.9/130 in the quarter.

[Dutt1113]

Originally Posted by jjscsix

I've seen credible road tests of M850s which should have performance basically the same as a 2020 M550. There is no doubt that it really does have at least 75 more HP. The numbers are there. BMW has always gotten more out of their HP than almost any other mfr.

And the 550 does not have to be tweaked to make the M5 look better. Motor Trend dyno'd an M5 at 600 at the wheels. And I've seen credible tests on them at10.9/130 in the quarter.

I'm not doubting the 2020 has more power. I just don't think it's as substantial as they make it out to be. The 18/19' are severely underrated and the 2020s might be slightly underrated or actually close to what BMW advertises. If I got an 18 I wouldn't be wishing I had a 2020 for the new engine power. I'd be putting either jb4 or Dinan or maybe even a flash tune to get around 600hp. I don't think the 2020 has bigger turbos (correct me if I'm wrong) it's probably just higher tuned software or just closer to its maxed out power than the 18/19s.

[modthispny]

Originally Posted by jjscsix

I've seen credible road tests of M850s which should have performance basically the same as a 2020 M550. There is no doubt that it really does have at least 75 more HP. The numbers are there. BMW has always gotten more out of their HP than almost any other mfr.

And the 550 does not have to be tweaked to make the M5 look better. Motor Trend dyno'd an M5 at 600 at the wheels. And I've seen credible tests on them at10.9/130 in the quarter.

The m850i has a much shorter first gear that helps the 0-60 tremendously. The new motor definitely has more power but an m850i will beat a 2020+ m550i due to gearing.

[jjscsix]

I have not seen a test of an M550, but I doubt there is much difference. The cars have so much low end torque that lower gearing will have very little difference. And the only difference it would make is coming off a dead stop. Once rolling it would make no difference.

Now that I think of it, one test I have seen that tells the difference is an X5. I've seen tests with the old engine and the new in the exact same vehicle. I'll have to look them up, but I think the difference was significant, especially for what is a much heavier vehicle. My memory is that trap speed in the quarter was 4-5 mph faster.

[jjscsix]

Just found the X5 tests. I was a bit off.

X5 5.0 456 HP. 0-60 4.2, 1/4 mile 12.7/109

X5 M50 523 HP 0-50 3.9, 1/4 mile 12.4 112

Considering the weight and much worse aerodynamics that is still significant.

[richard in NC]

I love my '18 M550i. The 456 HP is plenty and the car has few faults at all. My biggest gripe is the way the stop/start works. It's not as sharp handling as a full M5 but you get a nicer ride and save big $ compared to it.