does anyone know if 91 testarrosa wheels and tires will fit on 83 mondial?
Probably....I looked at a set of 91 Testarossa wheels on ebay, and they appeared identical to later Mondial wheels. If you are contemplating a set of Testarossa rims for your Mondial, I suggest you insist the seller verify: 1. that the rims are for 16" tires (not 415 mm, Michelin 415 mm TRX tires, not really available any more. 2. verify the bolt pattern is 5x108 mm. If they are 16" rims with the 5x108mm bolt pattern, they you should be good to go.
You got to define what "fit" really means -- if you mean "fit well" then the short answer is "no" IMO: At the front, the TR front wheel offset is too small (+34.2 mm vs +55 mm) -- this moves the wheel more outboard, so it probably will physically bolt on, but the steering geometry isn't right (because the wheel centerline has been moved outward ~1" on each side), and, with the extra width of the TR front wheel, the outboard sidewall of the tire will be out way past the coachwork. At the rear, the offsets are closer (+59.6 mm vs +55 mm), but the 10" width of the TR wheel probably won't clear the suspension/spring, so you'd probably have to run a fairly large (and expensive) spacer -- again moving the wheel outward beyond the coachwork. Here's a thread where Russ found a picture of a TR rear wheel mounted on a Mondial: http://ferrarichat.com/forum/showthread.php?t=68076 but it's sticking much too far out to say that it "fits well" IMO (even though it does "fit"). Have you considered the 16" MondialQV reproduction wheels?
