I have it for PS2. $15 at Walmart now. I've unlocked all the sleds now. Fun game that helps take the edge off waiting for snow.
I had the original version of this game on PC when the ZX was the newest chassis. You were able to freeride anywhere in that one without being dragged back to the track, and there were some pretty funny cheat codes such as super speed and low gravity which let you get some wicked air!

There was no backflip option, but you could do your own by using the above-mentioned cheats, doing a superman seat grab off a good launch and lean waaaaaayyyy back until you came right around. More impressive than a run-of-the-mill backflip IMO...