180 degree thermostat
Stock TC's run a 192 degree thermostat. Running a cooler one, 180 degrees, allows the engine to start cooling itself sooner, thus allowing you to run more advanced timing and a more agressive computer program. These thermostats are around $6 from you local parts store. No actual horsepower gain here, but it enables you to run a bit harder.

Exhaust
I bought a set of stock 96 Mustang headers, but after sizing things up, I don't think they will fit. I've heard of other people that have installed different mufflers, but most are very loud or too annoying to drive a lot. No major gains have been reported with aftermarket exhaust. Dual exhaust, however, is a must! See the link at the top of this page for upgrading to dual exhaust for single exhaust cars.

Fog light installation
A few considerations:

Headlight upgrade to HID
The Town Car's headlights are a single-bulb dual-filament setup. Unfortunately, this type of setup isn't good for HID conversion. When converting, we'll end up losing high-beam, as you'd replace the single bulb with the new HID single-filament bulb. Options seem to be live with no high-beams, or maybe add a seperate high-beam bulb in place of the front turn signal bulbs, or hook up some fog lights on the high-beam switch. Further study into this is needed!

Suspension Upgrades
Heavy Duty Shocks
Bilstien makes shocks that firm up the suspension and improve handling on these cars. The front shocks are easy to change--easy access to the top and bottom of the shocks. The rears, however, have good access on the bottom, but insanely tight access on the top.

The Bilstien info is:
Front: F4-B46-1495-W0
Rear: F4-B46-1496-W0
Avg Price: $70 each

The are the "HD" (heavy duty) model. There's also a "C" (comfort) model. Not sure how the C's compare to stock shocks (my guess is C's are somewhat firmer then stock). They may be listed under Crown Victoria--don't ask for Town Car as they'll give you a funny look.

Personally, I replaced my front shocks first. The handling improvement was very noticable. I recommend doing that and seeing how you like the feel. Changing the rears makes the car more boxy feeling and loses almost all of the "floatiness" of the suspension. If you like that, don't do the rears.

Finally, these shocks are very very stiff when first installed but loosen up a bit within a few thousand miles. Hang in there for a while if you don't like the stiffness right away, it gets better.

Swaybars
Swaybars add rigidity to the frame, helping keep the car steady when cornering. Addco sells a set for the Town Car. I haven't tried them yet, but others report good results. I believe they're around $120 each (front or rear).

Wheels
The Town Car wheels have a bolt spacing of 4.5" by 5 lugs. Other cars wheels have similar spacing and lugs, but the offset is different. Lincoln LS wheels, do not fit the TC, nor do the Continental or Mark VIII wheels. Mustang wheels generally fit, but they need a spacer to really fit properly.

There's really no other model that has direct-fit wheels for the TC. Let us know what you find in the aftermarket. Tire Rack has one 16" wheel available. Here's a link to it.

PI Intake Manifold