17X9 vs smaller diameter?

[fast84gti]

I currently am running 255/40-17's on my 1994 e36 318is. Team Dynamic wheels.
I love the handling. It's incredible.
I am curious if going to a 15X9 to save weight will not handle as well.
I am not sure how the contact patch will be effected.
I am going for weight savings. Yet I don't want to effect the handling in a negative manner. I am trying to find a ballance.
This car is getting lighter every time I work on it.
I do like these wheels for daily drivers as they are very strong.
Don't mind a little weaker wheel for the track.
Just want lighter, and good traction...
Thanks.
Todd

[Jim@tirerack]

Unless it is a track tire you are not going to find any good performance tires in the 15" anymore. I would stay with the 17" if it were me. If you do bigger brakes the 15" will probably not clear.

[fast84gti]

Thanks for the info. I also hear many people like to go UP to 18" because of the availability of tires.
A friend of mine did plastic arch flares so he could squeeze some 18X10 on his e36 m3. Handles like no other!
Guess I will stick with what I have :D