wheel sizing question
 

alright, so if my understanding and research is correct, our wheels have a 55mm backspacing. now, since those measurments are on 7.5" wheels, will that backspacing number be different on 7" wide wheels? also if i add a wheel spacer to correct the backspacing, will that be bad for the car?

On a 7" wide wheel you can run a range of offsets, I'd estimate anything between +35 mm and +60 mm should work. This is assuming you go down to a 205/55/16 tire, which is a perfect match to the stock diameter, and should fit a 7" wide wheel very well. As you reduce the offset though you'll be putting more stress on your bearings:( so try not to go too far.

If you happen to find a wheel with more than +60 (hugely unlikely) you'll need spacers, but otherwise there should be no problem.

Do you have a rim in mind?

my friend gave me a set, 17x7but theyre like a no name brand, never heard of them, and i dont know the offset, but when i tested them on the svx, with his tires, it looked like it may have been an issue with my newer bigger tires, and i cant even find the company on the internet. and heres the other thing, tires are expensive, and ive got 2 falken azenis st115 that are brand new i got from free from work, but the thing is, the sizes dont match when you go up a rim size, and theyre pretty big, and may not fit, and im sure the speedo will be way off, but its cheaper to buy to new tires that match those, then a set of 4. theyre 225/45 zr17.

225/45/17's should work well enough. If you look on the backside of the wheel, there is often information printed there that can tell you the offset. Just look till you see something that looks like an offset number, and that's probably it.

awesome, as soon as my brother gets home, im going to pull one out of my trunk and check. haveing this big of a tire/wheel package, will that affect my acceleration, and speedo accuracy?

A 225/45/17 tire will be almost an exact match to stock, so your speedo will not be affected. Your acceleration may be positively or negatively affected depending on the weight of the rim/tire combo. If it's lighter than stock, you'll accelerate faster. Heavier than stock = slower.

awesome, thanks!