When I get to about 45-50 mph I get some vibration, but it's not there at lower or higher speeds, just right around 45-50. What sorts of things typically do that, so I can start ruling things out and get it fixed?

 

With a speed-specific vibration, I'd start with the tires. If the tires are off the wheels, make sure your wheels are balanced, as well. I once had a really bad freeway shake that I traced to a bent wheel.

 

Ok, thanks. They are brand new wheels, so I hope that's not it. I'm trying to remember if it was doing it before I had the new wheels put on....and I can't remember. I didn't drive it much before getting the new wheels put on.