Actually, no: Pure's tracks do not have the same count of polygons compared to Pulse and I'm sure they may not works as good with Pulse's physics as they do with Pure's. Then of course you have to re-program parts of the tracks so they have both directions (as you said).
But I'm pretty sure Pure's tracks are esier to port than Fusion's - that's what I wanted to say.
And even though Pure's tracks are relatively easy to convert for PS2, it's probably still enough work you would have to put into it.