Genesis

Hi all. I get my 6MT 8 in Nov and want to replace the stock rims, but keep the Potenza tyres. The Potenza's are 225/45R18 on the stock 18 x 8 rims. I understand the offset for these rims is +50 and they weight about 21 lbs. My objective for this is mainly looks, but don't want to lose performance for sure (in fact, gain some performance if anything). By keeping the tyres, I guess I'm limited to 18 x 8 or even 18 x 7.5 rims (thanks EBS), but that's it, can't get wider width rims else I need new tyres. I'm sold on the SSR GT1's (awesome!), but Hyper Rev 96 lists them as 18 x 8 front +35 and 18 x 9 rear +38.

Question is, would there be any issues if I got four SSR GT1's at 18 x 8 for both front and rear? I could then fit the four Potenza's without problems. I've been looking for the GT1's weight, but no stats...anybody know if they weight less than 21 lbs? Plus, would the lower offsets on the GT1's be a problem? I'm guessing not, since I've read that rear wheel drive cars perform better with lower offset rims. However, I have no experience with this, especially concerning the 8.