In order to maximize future gains in horsepower, the stock 2.25-inch cat-back system had to go. The kinks and bends that aid in installation on the assembly line simply have no performance in mind. To remedy this, we opted for the BX AFT-CAT exhaust system.
The Quiet Thunder kit features aluminized mandrel-bent 2.5-inch tubing and Bassani's "Composite" construction mufflers. The mufflers feature durable Stainless Steel internal construction housed in a 16- gauge aluminized steel case. For 1987-93 Mustang GTs, order PN 5093GT5, which sells for $531.25.
On the passenger side, remove...
On the passenger side, remove the mass air elbow and if you still have them, the emission lines that run to the air pump. This will give you more room to work and you'll need it.
Since Bassani includes all of the clamps and bolts needed, installation is a snap. Ball and socket connections eliminate the need for welding and also offer excellent sealing characteristics. The step headers come as separate tubes, but instructions are included and tell you which order to install them in. Once you have them loosely hung, you can slip on the collectors and then the ball and socket flanges that connect them to the X-pipe.
The X-pipe features the proper factory hangers, as does the cat-back system. This makes installation for these parts a simple disassemble/reassemble deal. The tailpipes offer plenty of clearance around objects like the gas tank and upper control arms. Which keeps things rattle-free.
In the instructions for the headers, it mentions that some modifications may be necessary, but we found no issues that needed correcting as far as the headers were concerned. The long-tubes do relocate the O2 sensors farther back and, for this, Bassani recommends pulling the wires out of the harness to gain the needed length. We needed to re-route the "low oil" level sensor, which runs with the O2 sensor in the same harness. This seemed rather tedious, as re-routing the harnesses required quite a bit of Zip Ties to keep them out of the way of the headers. Get yourself some O2 extensions and be done with it.
The Bassani headers and BX exhaust system sounds great and fit well. We had hoped to bring you some updated track and dyno results, but the stock replacement clutch that was installed a few years back isn't really happy with the 300-plus rear-wheel horsepower and said "Uncle" more than once when shifting into fourth gear at the strip. Therefore be sure to check out our next installment of our Procharged pony for the details.
 Apply more penetrating oil...  Apply more penetrating oil here and then unbolt the header. If your car is stock, you may also have to remove the engine hook that the factory leaves on the headers. |  The driver's side has a little...  The driver's side has a little less clutter. The dipstick will mount back in the same location when you're done. |  Out comes the stock shorty...  Out comes the stock shorty header. |