Snaketer(cool name btw),
As per wikipedia......... "The Mustang GT's power increased to 260 hp (194 kW) at 5250 rpm and 302 ft·lbf (409 N•m) of torque at 4000 rpm via the new "Power Improved" (PI) heads, cams, and intake manifold. The new 2-valve SOHC 4.6L Mustang exhibited characteristics associated with a performance engine when compared to the performance behavior of the earlier 2-valve SOHC 4.6 L engines."
Regarding the Town Car.....
"1998-The Cartier model also received a 220 hp version of the Modular V8."
"A Touring Edition also became available in late 2000. The Touring Edition featured a more powerful 235 hp version of the Town Car's Modular V8 engine"
As per Sean Hyland's "How to build a performance 4.6L" book...."1999-up Performance Improved" included Heads/Intake/cams(I'm almost 99% positive)
Also....the Cylinder Head Volume/Flow data....
96-98 GT Volume "Chamber CC" 51(barely better) "Intake Port CC" 146
PI Heads "Champer" 42 "Intake Port" 159(Better)
The PI valve flow is WAY better on BOTH the exhaust and intake all the way up to .500" Valve Lift. The GT heads flow a smidge more at .550/.600" than the PI heads on the intake valve lift, but the exhaust flow is extremely better in comparison.
So.....for people to say "its gonna drive like a TC", tell them to prove it or STFU. And like Matt said....more torque/hp in a lighter car is more power for the punch. As far as the numbers go, the PI setup is WAY better than the 96-98 GT setup. As far as internals go....I'm not sure. They may be made of different material but I can assure you that the PI engine is going to run/perform much better than his GT engine. And yes....you NEED to use the TC computer and that will deligate how the engine runs. Once he tunes it or gets a chip, he will be able to turn all the crap off to "de-tune" the TC engine and get even more performance out of it.