Especially Aston National for example the xxr isn't ttat much in advantage for longer turns. I've already seen races where a FZR drove 1.43 every lap oder a 45 laps distance , he had to do one pit stop more thats true but he was able to gain the time for it on track, the fastest xrr just drove 1.44 so the fzr wins a second per round.
Regarding the FXR, i like this one for real but he is simply to slow The FXR is the best starter, starts even better than the FZR but this is senseless for longer races therefore the gap to the other GTR's is to hugh.
The FXR has a loss of 10 km per hour on the long straight at Aston National against FZR and XRR this is simply to much.
And the XRR ist more tire friendly than the FXR, just try it, you have to push even more if you want to be fast with the FXR so you're ruining the tires much faster than the XRR!