I wouldn't waste money on the Commander unless you have the cash to spare...it won't do much except provide monitoring of knock while driving around without having to have your laptop hooked up. and the Commander is useless for the most part for tuning purposes. MWR still might be giving them out free with their PFC's though. and I would get the PFC from MWR since it comes with a pretty good basemap which of course needs tuning.
FCDatalogit is the thing to get.
there are three sources that I know of...
Rotary Performance (out of TX)
(who supplies MWR actually haha)http://rx7.com/store/rx7/fdecu.html#powerfc
straight from the makers in New Zealand:http://www.fc-datalogit.co.nz/http://www.fc-datalogit.co.nz/buynow.htm
though you'll pay a little more, maybe get it faster...
it is coming from NZ so maybe you'll want the insurance and then that's $400 total.
I got my PFC through MWR first and then had to wait many months for the backordered Datalogit. not suprisingly Rotary Performance called me first before MWR (who would just charge it when available) so I went with Rotary Performance. I think it was like $351 shipped.