I have one of these in the 4-inch barrel, ported. Sweet gun to shoot. BTW, according to most sources I have seen, the Taurus Tracker is one of the few handguns that will handle the 45 Super without modification. So.. you can shoot 45acp, 45acp +P, and 45 Super out of the Tracker.
Also, make sure you order some spare 5-round clips. They can be found on the Taurus website.