6-8lbs of boost is all I'd run thru a stock motor. Much more and it will blow a head gasket in short order(or the bottom end?).
Headers? Unless you find a set of shorties that you can turn upside down I think a std set for that truck will be a problem. They'll have the pipes into the radiator/hood if you turn them upside down.
Exhaust? I'd run a short dump tube just like most of the car guys. You dont want any restriction after the turbo or will slow down the spool up of the turbo. The turbo is the "backpressure" for the motor.
To get rid of the high speed shut down, you'll need to find a manufacture of a chip for your truck and hope that it has that option. If I recall my '97 F350 was about 95mph? then it shuts down. Not sure if it's just ignition or fuel also? can't just bypass with an
aftermarket ignition, as if it shuts down the fuel you'll burn it up with a serious lean out.
A race track with a 5 mile run?? Is this a road course or what? never knew a race track with 5 miles of straightline. Even the Silver State run isn't that long and they run 200 mph. Your truck at much over 100 will be a death trap with the aerodynamics of a large brick, let alone the
tires aren't rated for that kind of speed.
Good luck with your project.