Luckily I have a friend that is a tire designer for Michelin/BFGoodrich so this is something I can shed some light on. The G-Force KD is about the same section width as any other similiarly sized tire. The difference is in tread width. I know someone will look at the specs on
www.tirerack.com and say the tread width on the G-Force KD is less than the AVS Sport, but that is just the way it's measured. If you look at the G-Force KD you will see the tire has a very rounded shoulder. This design lays a lot of tire on the road while cornering, but doesn't give you the largest tread width while sitting still. If you lay a straight edge across the tread of the G-Force KD and measure the width about 1/4" down the side of the tire, this is where you will find the G-force KD is around 5mm wider than it's competition. This is also where our rear tires tend to hit the fender lip under typical suspension travel (higher speed cornering with street tires). You could run less than a 55mm offset on you rear wheels and never get rubbing with the 295/30 AVS Sport, but you would rub with the 295/35R18 G-Force KD. Yasir, your offset is enough that running a 295/35R18 G-Force KD wouldn't be a problem, but you wouldn't want to run a tire that tall anyways (26.1" vs. 25.0" for stock tire). You could run the 285/30R18 G-Force KD, but it would be smaller than your 295/30R18 AVS Sports. Here are the specs on some of the mentioned tires
G-Force KD
285/30R18 Section width 11.4", Tread width 9.4", and height 24.8"
295/35R18 Section width 11.9", Tread width 9.8", and height 26.1"
AVS Sport
295/30R18 Section width 12.0", Tread width 10.6", and height 25.0"
295/35R18 Section width 11.8", Tread width 10.6", and height 26.1"
A couple of notes about the above dimensions. The tread width of the G-Force is not representative of their actual width (see comments above). The AVS Sport is actually 11.8" section width and not 12.0". The above 295's were measures on 10.5" wide wheels and the 285 was measured on a 10" wide wheel. If you mounted the 285 on a 10" wheel, it's section width would probably go up about .2".
Hope this helps, Steve