haha yea i got an R31 as my first car, still have it and its been very reliable. plus its dirt easy to work on, with stuff that you need to take to a mechanic being able to fixed with a few tools in your garage.
plus all the newer RB engines drop right in and gearbox bell housings are all the same so you can mix and match or have a few spares for cheap.
also, its not a boat like the falcons or commodores, and it can carry 5 people comfortably, unlike the little 4 banger hatches.
and they dont get as much police attention as newer skylines and you dont see many modified ones much, so its more unique
if you buy an R31, get a silo or a Ti and check out www.r31skylineclub.com for cars for sale and any tech info you need.