After checking around and getting crazy high quotes to mount a 300, I did mine by hand in the garage (lots of go-jo, 2 flat bars & 1 helper holding pressure). As far as getting the old one off, I cut it off with a razor and snipped the steel cords in the bead. It was not the easiest thing in the world but I'm not giving $100 to mount a tire.
My cuz / Moedog found a tire & wheel place in Knoxville that does lots of the new / high-end car wheels (20's with very litte sidewall etc) and they said no problem, they would mount them for $20. They did a nice job on his. I'm heading their way next time.