Skylines are not expensive to maintain if you purchase a good one at the start, get a trusted mechanic to go over it and do all the coresponding enging checks (eg, leakdown test, compression test ect...) as engine rebuilds are about $5k for a reasonable build. I got mine checked and it has run like a dream for 2 years now, the only time it was off the road was my fault . Also if you are chasing second hand parts there are lots of them going in the for sale section on SAU there is also a wanted section so you can post there and get parts that way. If you would like any more information give me a PM and I will point you in the right direction, but try a search first as just about everything you could need is on here somewhere.
Chris