I grew up outside of Great Falls, lived all over the state until 95, when I decided I wanted to have enough money to buy more cars and moved to Portland.

Since it's been a while, I can't say for sure, but I don't think you'll find a "real" dragstrip anywhere near Columbia Falls. Circle track is about the limit of the track experience for most of the state. But, hell, you've got miles and miles of straight highway with minimal traffic, so it ain't so bad! Tuner's will be tough to find too. Missoula is probably the closest bet from C. Falls. I knew some good guys there, but that's been almost 15 years now...
Bison Ford in Great Falls is decent, was an SVT dealer, and still gets a better selection of Mustangs than the other dealers in the state.
Beautiful place to be. But, the economy sucks and there isn't much to do but ski, hunt, fish, camp, wrench on your cars, and talk to your dog. Oh, and drink. Usually during all of the above. Good luck!