You will want to run some sort of TRE to de-limit the motor.
The motor is limited to 180 mph (2001-2008) [99 and 00 were not limited] electronically.
Another way to de-limit the motor and the method I use is to use a modified GPS, then the motor sees all of its stock timing and fuel curves and only sees 6th gear as 5th but as I own both (TRE on bike and GPS on car) I cant really tell much difference between them as far as how the thing drives.
The one advantage to a modded GPS is you can mount a gear position indicator to it and see what gear you are in. This has been a big help for us because the tranny ratios are so close that it is hard to tell what gear you are in and can easily keep try to shift into 7th.
This is the modded GPS and gear position indicator I used.
http://boostbysmith.com/pb/wp_0ec87766/wp_0ec87766.html?0.7051036358049676Cost for indicator AND modded GPS: 75$
Greg Smith even custom made a ours with a very long tail (10'), plug (for quick disconnect) and a red LED for 6th (all other gears are green) for no extra.
The modded GPS will also allow for future use of a gear based boost controller (allows for selectable boost settings in each gear, so 1st will only get 5 psi, 2nd will get 10 psi and 3rd will get 15 or whatever amounts you adjust it too in each gear. Helpful for drivability with high boost and it can be a handful to make 500 HP in 1st gear!)
Good product.
-JH