[elvin315]

Originally Posted by Brosepe

Do they not fit because the GTO calipers require a larger diameter wheel or because of the width of the wheel? Could I uses some wheel spacers to gain more clearance?

Spacers won't help. The inner wheel surface won't clear the calipers unless the wheels are at least 17 inches. New wheels don't have to be expensive. There are always bargains on eBay. The Tire Rack has a nice selection of Catera wheels ranging from $89 - $199. Add tires and maybe they'll give you a discount. They have more expensive ones too.

Beware: Not all the wheels listed on eBay for the Catera will fit the Catera. Remember, if you want them to fit and not ruin the handling, or destroy the wheel bearings, they must have a 5x110 bolt pattern and, depending on the wheel, a +35mm to +45mm offset. Offset determines the wheel's inner and outer clearances. Follow the link to an explanation of offset and how to measure it. Or you can use the Offset Calculator.
http://www.yokohamatire.com/utcustom.asp
http://www.1010tires.com/WheelOffsetCalculator.asp
https://www.rsracing.com/tech-wheel.html

Supposedly, wheels for the following cars will also fit the Catera (97-01). Verify before paying.

Chevrolet Cobalt SS Supercharge/5lug 05-07
Chevrolet HHR LS/LT 06-07
Chevrolet Malibu LS 04-07
Chevrolet Malibu LT/LTZ 04-07
Chevrolet Malibu Maxx LT/LTZ 04-07
Chevrolet Malibu SS 06-07

Pontiac G5 GT 2007
Pontiac G6 Base/GT 05-07
Pontiac G6 GTP 05-07
Pontiac Solstice 06-07

Saab 900/5lugs 94-97 (needs stud kit)
Saab 9 3 99-01
Saab 9 3 02-07
Saab 9 4 93-98
Saab 9 5 99-07

Saturn Aura XE/XR 2007
Saturn Ion Redline 05-07
Saturn L-Series 00-05
Saturn Sky 07-08
Saturn Sky Redline 07-08

Wheels on eBay
http://search.ebay.com/search/search...els&category0=

The Tire Rack
http://www.tirerack.com/wheels/resul...ar=&sort=Brand