96 Cobra rims to 05 bullitt rims

I have a 96 Cobra with the stock 5-spoke 17X8's with 245/45/17's.

I recently picked up a set of bullitt rims of off an 05 GT with 235/55/17's.

Question is are these compatible? Do I need wheel spacers, if so how much? and If I really wanna use the thicker sidewall tires; how much will it affect my speedo and driving characteristics?


Just put a new Motor in 'er... been 3 weeks already got 1k miles on it!! WOOOOOOOOOO!

so.... yes they are compatible? okay does that mean I can just bolt em on no prob or do I need spacers? And the 05 rims were aftermarket to begin with and Im not sure what width they are, but my stock wheels are only 17X8 so I dont think they'll look puny at all.