You'll love the tru-trac. Best option out there.
Here is a link that will assist you.
Speed/Tire/RPM calculator
With the taller tire (which is the one you should run) and 3.23 gears it will turn 2500@61MPH. Without an overdrive you might tolerate 3.55's but I wouldn't go beyond that on if you highway it much. To give you an idea of what a dynamic difference that would make for you, I run 4.56 gears and turn 2600@ 60mph
Moving the rear back will depend on the rear end cover you use. I needed to shim mine back but I also run a welded factory replica fuel tank. A stock tank and a stock over should fit. Shimming it back is easy.
Suspension aside from springs or Tbars get some viking adjustable shocks. I'd call bill at RMS. He wons the site I linked you to.
