Certain problems with the R&D. 1)there are no bits made for them anymore. Everything you need has to be made bespoke. 2) Don't put anymore than 550/600nm through it. It won't last. 3) If you are on track and you go off, don't select reverse very quickly and give it big footfulls, revere gear is tiny. 4) you don't get an active centre with handbrake release.

You probably paid around £4k for it. It's a dogbox, everytime you change gear its already wearing out. This is where spares are important.
They were at the time the cheapest upgrade to a GrpN car then cheaper than an FFD for upgrades close to GrpA.
Just check first gear ratio, some of them were almost a second gear they were than tall.
Good luck with it. I hope it lasts for you.
The Skyline is a very cheap high power handling option with better features if you need that kind of technology.