i hate people that have no idea what they're talking about and try to make it sound like they know what they're talking about.
thats some horrible advise.
ok, here is the deal
what he said is only true when you get a 17" wheel with the wrong tire size. for example if you got something stupid like a
215/40/17
your overall wheel diameter would decrease. therefore giving you more rotations in a shorter amount of time, thus altering your speedometer and odometer readings. it does not necessarily affect your "accelleration"
the ideal tire size for our car is
245/45/17, which is the stock size that comes on all GT's.
fitting issues are not a problem as long as your offsets and widths are within specs. 17x8-9 should be fine.
i am not going to lie to you tho. it is a fact that switching from our stock tire size to the 17" wheel with 245/45/17 tires will still decrease overall wheel diamter. BUT, the difference is caulcated to be within 1-2%, which is miniscule. the affects would be unnoticeable. however if you're picky, you can recalibrate this with a speedcal unit, which is what you must get after changing gear ratios.