congrats on the car and have fun with it, WHEN it arrives
now as for the "stable as 335i" i might agree with you and add on a few things, since 135 and 335 are based on the same engine and performance upgrades like brakes and drilled rotors and so on, the reasons why 135i might even out run 335i is because it weights a lot less and since you got the premium pack and all that once you modd it i think that pretty much you can outrun any 300 hp car outthere
so nice choice on the car and i drove it once and i also have to agree that those brakes and acceleration are much better due to its weight and its lighter chassis.