did you find it better running wider wheels up front and if so in what way?
im thinking of running 9's or 10s up front and 8's on the rear.

 

For autocross I tried 15x7.5" wheels up front, 15x7" wheels in the rear with 205/50x15" tires all around. Worked much better for me with almost a stock suspension. Turn-in felt quicker, grip was definitely better and compared to my peers in my class I gained about 1 second on a 60 second course, whereas before I was neck and neck with my competitors.

 

For what purpose?

 

time attack and hill climb

 

Sure, but, I run a 275 Hoosier on the front of my car on a 10.5" wide wheel, and a 205 Hoosier on the back mounted to a 6" wide wheel. On equal size tires, the advantages are not as noticeable. In general you get crisper turn in, can run a slightly lower tire pressure, and depending on the tire may see an increase in peak grip.

 

Similar to ^^^ 275's on a 10" rim in front, 225's on a 7.5" rim in back. Increased front grip with reduced track and weight in the back. Car handles great without any sway bars and slightly stiffer spring rates in front (yes, I know, I didn't believe either until I saw it with my own eyes).

 

i ran 250mm advan slicks up front with 225 hoosiers in the back. worked surprisingly well.

stock DX bar up front, nothing in the rear.