Don't get me wrong. I said that FZR/XRR were kinder on tyres, in the way they could run a softer compound(R2) on fronts. The FX2/3 can't realistically run more than a few laps on R2 on fronts since it is 4WD, and will get some bad tyre heat on front straight away.
On long distance though, the FXR is quite good with tyres, probably better than the FZR, and more or less as good as the XRR. Especially since it has a great handling, so you can easily maintain the tyres in a great shape all stint long. If you have trouble running 1 hour on one set of tyre, you probably are too agressive on cambers.