I've played it some more recently, and:

Klies Bridge: mirror of Talon's Reach with a straight starting grid.

Qoron IV: mirror of Altima, but butchered beyond recognition. The entire second half (after the elevated banked corner) is gone, as is the initial chicane, and the crest has been flattened.

Sokana: mirror of Korodera, but much of the track has been removed. The part between the three bends after the starting line and the right hairpin leading into the tunnel is new, getting rid of some slow track with lots of kinks, a split and another elevated triple 90° section. Also, a mild chicane after the starting line has been removed and the starting line moved up, making room for the longer grid.

Dyroness: mirror of Karbonis; the only real change was the removal of the initial S-bend to make room for the longer starting grid and the pitlane. (By the way, unlike in 2097, I strongly suspect that the pitlane is in fact identical for each track)

Machaon II: mirror of Gare d'Europa, with one difference; the three bumps that grind you to a halt just before the jump have been replaced with a single bump that grinds you to a halt. I think the pitlane is less angular as well.

Terafumos: mirror of Silverstream! Too bad they neutered it. The layout is the same, but each of the three splits had one leg removed. Moreover, the second and third split kept the 'bad' leg and lost the 'good' one, making the track almost unrecognisable. Also, the 180°-90° double hairpin in the tunnel has been replaced with a single wide 90° corner, and the 90°-45° chicane at the end is now just a 45° bend, presumably to fit the starting grid.

(Then again, the starting grid had a kink on the original track in WO1. The '64 team must have been obsessed with straight starting grids and hated splits!)

Velocitar: woot, some original development. The only original development in the other tracks are the wide corners on Sokana and the ruination of Qoron IV. Needless to say, Velocitar sucks. They had to cheat with the AI to make it challenging, and you can exploit this by activating autopilot at the right time to receive a rocket boost.