Dwightdmagee is correct. the Conti's I had were "squarish" and the Pirelli's have a VERY round sidewall. I first encountered rubbing issues on the INSIDE of the wheel well. I corrected that with a mallet and 20mm spacers! Once I put the Pirelli's on, they rubbed on the outside of the fender. Rolling the fender is not going to be easy, it is very thick, double walled steel. I had to go to 12mm spacers and now they rub on the inside again! Modding the inner wheel well would seem to be the easier way to go.
Please keep in mind that my car is lowered and has 1/2 in. wider rims.



This pic is with the Conti's ( no spacers yet )