Hey Dementors those are some great times on street tires. I think you made a good decision on the 18" rear wheels as many here have told me my 20" rear wheels are hurting my times. I have a set of 18" all around for road course track days that I had on the car for about an hour just checking the set up out and the car felt noticably quicker.The 18"s should also help with the clearence when you drop her.