I have a 92 525i, iwant to buy 18" wheels but i need to know what is the maximum offset i can use to achieve the most deep dish apperance i can get. The rims I want are the DIABLO VIENNA 18", 7.5" wide. I know the offset in my car is 20mm but can I use a smaller offset like 15mm or 13mm to achivev what i want, please help me out on deciding on the best offset and the appropiate tire width for my 7.5" wide Diablo rim. Also will a 15mm or 13mm offset rim show a difference from a 20mm rim, will i see the difference or is it too small to differ.