I know there are a multitude of different lowering options out there for our cars, but I don't like they way some of them look. For example I have seen a lot of cars where the rear end sits lower than the front. I know that the eibach pro kit is supposed to give it an even drop, but I have seen some some cars with these springs that the rear still sits lower. I also know the only way to get the exact drop you want is to go with CO's, but I have had nothing but problems with them in the past. You can never get the car to sit level, they leak, etc.
I plan on running 20x10 in the rear with 275/30/20 tires and 20x8.5 up front with 245/35/20. First of all can I run the pro kit with these big wheels and second will it give the car a raked look. I really don't want the rear tire to tuck in the fender like I have seen a lot of the IS cars doing, especially with the GS springs, that looks awful to me. Also what offset am I going to need to minimize rubbing and not need wheel spacers?

 

245/30/20 rubs according to some comments in the aftermarket wheel thread, 235/35/20 rubs when the wheel is fully turned so 245 will rub earlier

 

so would a better combo be 20x10 and 20x8. Because a 235 on a 8.5 wheel would be stretched a little far. On my S4 I had 245 on my 8.5 wheels and it was good.

 

245's on 8.5's do look the best.

The problem you'll face is that anything bigger than 225/30/20 (I don't even know if anyone makes a tire that thin) may rub due to the fact that the overall diameter AND the width contribute to the rubbing, not just the width.