go.....

 

Stock is 195/55/15. I've got 195/55/15 S.drives on 15x7" wheels and it's a great combination. Good turn-in and feel from the low unsprung weight, less roughness because the sidewall is reasonably sized, and still good performance.

There are a couple reasons to go larger (e.g. to 205/45/16 or 205/50/15). Increasing the width has subtle effects on cornering. It will slightly decrease feel and slightly increase max cornering g (I believe). Some people also think 16's look better, and they clear large brake packages. Larger wheels/tires do increase unsprung weight, however. And if you're seriously into race performance because you autocross or w/e, you might want to go up to 215 or even 225 width tires on appropriately wide wheels.

Here's pics of my car on 15" Konig Feathers (less than 12lb per wheel):

 

i personally like 16 or 17s with some low profile tires, fills up the wheel wells a little more.