Originally Posted by S-Dot
I think slightly stiffer springs, maybe thicker roll bars, and maybe a steering tweak will help the 3 series. It doesn't need much, really.
Personally, I found the 328i a much better corner-carver than the 335i. But I bought an xDrive machine, which changes the equation entirely.
There isn't much difference at all between the 328i sport and 335i sport in terms of handling. Both are built on the same chassis.
The 328i has slightly less weight up front, but that only gives initial steering a slight advantage. I changed the tires on my Msport to non RFT's and the steering response has improved, it now has a slightly lighter and quicker response.
The handling difference between the 328i and 335i is very slight and mostly shows its self on a track. Over all both versions are pretty much the same for the obvious reason, they are on the same chassis.