Here's a quick how-to for the Thermal exhaust I installed on the 91. It was fairly easy to do, especially with two people, and I really love the sound of the exhaust - not too loud...
I chose to use photos of the exhaust already removed for better visuals, and because the photos from under the car didn't come out very good. Let the car cool down some and spray all the bolts with Liquid Wrench/WD40 before you get started. We ended up using a socket set, open end wrenches, vise grips, a set of jack stands, safety goggles and gloves.
Parts Installed
A Thermal R&D 3 inch stainless steel cat-back exhaust, Buschur Racing
stainless 2.5 inch downpipe and a Catco 2.5 inch catalytic converter.
Step 1
Remove the 2 bolts that hold the downpipe to the O2 sensor housing and the
1 bolt that holds the downpipe to the heat shield (the hanging bracket below the flange).
Step 2
Remove the hanger-bolt just before the catalytic converter. Notice all the oil and grime?
Can anyone say, leaky transfer case!?!?
Step 3
Remove the 3 hanger-bolts in the midsection of the exhaust.
You'll likely need to brace the exhaust soon so it doesn't hang down.
Step 4
Remove the 3 hanger-bolts that hold the rear section of the exhaust to the car.
It's easy to access these bolts with the rear wheel removed.
Lower the whole system and slide it out from under the car.
Step 5
Here's the 2 systems side by side. What a difference! Installation is opposite of removal.
I found it easier to bolt all pieces together loosely and tighten it all down after the whole system
was bolted to the car. Start it up and check for exhaust leaks, and be careful with the speed bumps.
As a follow up - after about two years of owning this exhaust, I'm very happy with it. I am still happy with the tone, even though it seems like it's a little bit louder than it was the first few months. It may just be me.
One thing about these exhausts, is the they are 3" all the way up to the point where they connect to the cat converter. There's a step down to about 2.25" to mate up to the factory cat - well since I have an aftermarket 2.5" cat, this obviously causes a restriction. I haven't had it modified yet (mainly because I'm too lazy to go down to an exhaust shop) so I have yet to see how much difference it's making in power. I'd assume it would be noticable.
Other than that, I'm happy with my choice. It looks good, sounds good, and looks like it will last a while. I would defintely recommend this system to anyone. It's not too cheap (about $550 at most shops), but it's worth it.
