Yeah. Check over in the Modular Forum.
But all the sames sorts of bolt ons that people have been using on the 5.0s are now available for the 4.6s.
The first thing I would do is get a set of gears. 3.73s+ for the GTs, 4.10/4.30+ for a Cobra. Then a shifter. For bolt on power there are underdrive pulleys, timing adjusters, and intakes. For the exhaust there are several different headers available now in both shorty and long tube configuration, several H-pipes, and who knows how many cat-backs. There are about 10 different manufactures of superchargers.
Steeda carries most of this stuff:
http://www.steeda.com/
BBK makes a nice set of long tube headers and some other stuff:
http://www.bbkperformance.com/
JBA makes a couple of nice (although expensive) sets of shortie headers:
http://www.jbaheaders.com/
And it goes on...