E93 weighs just under 400 pounds more than the coupe for the 335i.
Coupe - manual/auto
328i - 3351/3417
328xi - 3582/3627
335i - 3571/3582
328i - 3792/3858
335i - 3946/3957
I have an E93 N54 and love it. It's not as rigid as a coupe, but is one of the best cabrios I've driven. It also has the benefit of having a lower center of gravity when the top is down, which is a noticible change in handling.
Have a Cobb, everything else engine related is stock (well, did add an oil catch can, but that's not performance related)..
2007 E93 N54
Last edited by andrew_b; 11-21-2012 at 02:00 PM.