1: yes, track IR is a must. Thank about it, all you have to do is move your head, just as you would IRL!
2: I don't quite understand...
3: well, i wouldn't like that my self, but as far as I know, no.
this was mainly to answer your Track IR question. If your going to spend money on a new PC, then $150 won't hurt you too much. I got it a year ago, i loved it within a week and can't imagine lockon (or any sim) without it.