
The rear disc brake upgrade...

The rear disc brake upgrade and SN-95-length axles forced out our Fittipaldi 17x8.5 wheels far enough to rub the fenders.

The caliper/rim location is...

The caliper/rim location is the first clearance issue to look at. If you're good here, you can move on to the spoke/caliper area.

Knowing the S197 Mustangs...

Knowing the S197 Mustangs have some pretty comparable brakes, we figured we wouldn't have a problem clearing our Cobra calipers-and we were right. It was close spoke-to-caliper, though, with about 11/44-inch gap.

The strut posed our biggest...

The strut posed our biggest problem fitting the 18s. With the 17s mounted, we had a good 3/8 inch of clearance.
Woodview
Thanks to Woodview, Mustang owners can replace their car's stock, plastic trim with either classic wood trim or race-inspired carbon-fiber pieces. Woodview has three trim lines from which to choose. The Woodview line is a molded dash kit with wood-appearing trim. Next is the Heritage line, which features premium-grade, genuine wood trim to enhance the interior appeal of your Stang. If you are going for the race-car look, Woodview has you covered with its Dash Tek trim line. The Dash Tex kit is made of carbon-fiber, Kevlar, and glass-weave items, and will turn the interior of your Mustang from sleeper to racer. Call Woodview for applications and pricing.
S197 Wheels For your Fox
Bolting SN-95 wheels to Fox-body Mustangs is nothing new, but some have now tried it with the S197 Mustang wheels. The extra offset of the S197 wheels is especially helpful in SN-95 rear disc or 2300-K kit applications as it tucks the wheels/tires under the fender for a more factory appearance. While Ford Racing Performance Parts still offers the Cobra R disc-brake conversion for Fox Mustangs, it no longer carries the special offset Cobra R wheels.
We found the S197 wheels to fit better than the SN-95 rims, which have a tendency to stick out a bit too far. If you plan to use the SN-95 rims, we suggest getting a set of rear caliper relocation brackets from North Race Cars, which will allow you to run stock-length axles, thus bringing the wheels under the fender lips.
If you want to keep the brand-new axles that came with your 2300-K disc brake upgrade, then the S197 wheels are for you. We decided to try out a few of FRPP's wheels for looks and to see how the different backspacings fit on our Cobra R disc brake-equipped ProCharged Pony Fox Mustang.
The optional 18x8.5 wheel with its 6.29-inch backspacing just doesn't offer enough back-spacing for the Fox, at least in the rear. Up front, the 8.5-inch wheel was dangerously close to the front strut, so on to the next wheel.
We had hoped the 18x8.5-inch Bullitt-style wheel would fit, as we liked the extended spoke look over the 17s, but it was not to be. With their 6.82-inch backspacing, these hit the front strut, and both 18s rubbed the rear of the lower control arm up front.
The 17x8s were the winners with their 8-inch width and 6.29-inch backspacing. At $140 each, they're quite reasonable, and they clear the front struts as well as the rear quarter-panel lip.
FRPP offers several wheels...
FRPP offers several wheels for '05-'06 Mustangs. From left to right are the 17x8 Bullitt-style, the 18x8.5 Optional GT wheel, and the 18x8.5 Bullitt-style wheel.

You'll also want to check...

You'll also want to check the clearance to the inner fenderwell and things like brake lines.

With the S197 Wheels, tire...

With the S197 Wheels, tire rubbing on the rear fender lips was resolved thanks to the added backspacing the S197 employs. We could actually use a tad more backspacing on the rear wheels to fit a wider rim/tire combo.

With the 17x8 wheels, we opted...

With the 17x8 wheels, we opted to use Nitto 555 radial tires sized 245/45/17 on our project ProCharged Pony. With its copious power output, Nitto recommended its sticky 555R Drag Radials for the rear, which will give us added traction at the strip, along with good street manners and wear characteristics.