I have HR race springs and am not completly happy with the stance. It could be a tad lower. I am going to buy AFS 18 inch factory reps. Will these close the gap up a little more or will the lower profile tire make it near the same as the 17 inchers?
It will probably close up the gap somewhat but not much. I was in the same position as you and wanted a tad lower stance with my Race springs.
You could take out your ISOs or just get new springs. I, personally got new springs, Eibach Sportlines and love them. I have some before and after pictures if you want to see them just holler at me to get an idea of that.
Go to Tire Rack's (or some other vendor) website and research the overall diameter of your current tire to the overall diameter of your proposed tire size.
For example, when I was running 315-35-17" tires, the overall diameter was 25.7." Now I'm running 295-35-18 tires and the overall diameter is 26.1." So, by changing from a 17" to a 18" tire, the overall diameter increased by almost 1/2">>>
before the 18/10.5 Saleens(I have Eibach Pro-Kit with NO ISO's) 275/40/17 Goodyears all around
After 265/35/18 BFG KDW in front 315/30/18 BFG Drags in the back
Rolled front fenders, back are not and I only rub in the back/front on deep dips in the road or a real big dip in the road going fast>>>> this setup needs the low profile IRS bolt from M&M