[luckyu]

My understanding from those that have tried it, is that the springs will very likely fit, but they will jack up your 328 by at least an inch, probably more like 2 inches...

I've been thinking a great deal about using various springs, and I think 335 owners should experiment with the various lowering springs available for the M3 (Eibach etc). The ride height of those springs used on a 335i should end up close to e9x sports suspension height (14" in front). So that may be the ticket there -- if your goal is to get (close to) the M3 rates.

But the stock M3 springs don't seem to be practical on our cars. The M3 sway bars work great, and if you wanted to switch over your rear camber link to M3 style, the rear shocks you can use as well, if your friend's getting rid of them.

If anyone wants a front spring for the 328i that is very close to the M3's spring rate, and gives a 14" (approx.) height, I would suggest the BMW Performance yellow spring for the 135i coupe. The only risk is that the ride height might be a little different 14".

For the rear spring I think it's better to go with standard race springs + height adjusters, to get exactly the matching rate & height you want.

You can get Hyperco race springs for $55 each at shock-shop.com, and height adjusters are about $150 - $200 a pair from various vendors.