My favourite three at the time of writing: XR GT, XR GTT & UF GTR
I never wanted the UF GTR to replace the LX8 GTR, and wish we had both not one of the two, but damn that UF GTR is a fun little race car despite being FWD
XR GTT is so much fun after S2's improvements... hated racing it in S1 (enjoyed drifting it though), but I refused to be a FXO driver as 95% people used it anyway and the RB4 was only good when racing those who weren't FXO aliens
XR GT will always be my favourite, it just feels so balanced and natural. Probably because it's similar to most the cars I've owned/driven.
In S2 I've barely driven these cars; FZ50/FZR, RA, LX4, MRT5 or XFR. I don't think I've driven the S2 version XF GTi unless it was for smash ups either. Hope to give them some time later on and see if my top three changes