The rears are 17x9 27+ the front have the 35+ offset. Actually the more positive offset the further in it will move the wheel. My wheels fit perfectly, gets as close as possible to the fender without rubbing. As I said before the 17x9 17+ was actually flush with the fender, but if I hit a big enough bump they would rub so I had to import the 27+. I believe the spring is there to help hold the line up to give it range through the suspension but can bend if needed or maybe for vibration. Obviously I really don't know why it's there. Hehe. I really like the s-tech, they are a progressive spring so over small bumps they ride pretty normal, hit a big bump and you better hope the t-tops are off or your head might hit. That's only happened once. I have stock struts.