Help! I need to know the largest rims that will fit on a '90 Volvo 740 GLE

[Reduccini1]

Hi all. I had a quick question concerning a bet I made with my friend about the largest size rims that will fit on a 1990 740 Volvo GLE. My friend was telling me that he could put 20"s on it (w/ modications of course), and so I also wanted to know, if this is humanly possible, would the car have to be raised? What else would be necessary to achieve this? I think the stock size of his car is 15"s, so I was trying to tell him that at best, IMO 18"s would be stretching it. Since he really doesn't drive the car that often, also we wanted to know of any effects this will have on the performance. Thank you in advance for your help...

[Luke@tirerack]

the largest we offer for your car is 16" but, I have seen 17's