I am looking for some input on what offset I will need to put on a 18x13 Wheel. I am going with a 345/30 or 35/18 Tire. I am not doing anything but needing traction. Alot of it! I will have stock brakes in back. I do not mind modifying the rear fenders to fit the tires. I am just really confused by all the offset articles I am looking at. I have PIAA Super Rozza 19x10 I think maybe 10.5 on the rear now. It has offset of 23 I think. It scrapes the fender. If I could fit 18x12 without modifying the fender or 18x13 that would be awesome. I just do not understand the offsets. Thanks. This is going on a 2002 Lexus GS300 with Tein Flex and about 1100whp.