Alright...I know that if I plan to have 8.5" wide tires on my 89 300e with 225/45/17 rubber, then I will have to perform a fender roll...I have two choices: rent the fender roll tool from tirerack and pay only shipping or pay the BMW-Dinan dealer here 150 to roll them for me. What I need to know is what exactly is fender rolling. What does it do to the car, and what parts are affected? Is it simply folding the inside 1/2" sheet metal that extends from the fender inside the well or is it "pushing up and out" the WHOLE fender region? I want to know this before I contemplate doing this myself, or even before letting the dealer do it so i know i wont get ripped off. THanks.