1 of 2 things happend here...1) you got lucky with a cheap car (doesn't sound like this is you) 2) you paid a small price for a car thats going to cost you a fortune to fix...its been used in RWD mode, obviously for a while, gearbox sounds like it has issues at best....i think it's going to be trouble street for you mate. Start working extra shifts...because its going to cost you lots. Btw "da" isn't a real word and neither are a lot of the other ones you use...grammar is your friend...good luck with the car...and good luck getting insurance as you sound like your straight out of (or still in school) and you won't be getting cheap insurance on a GTR under 25....that 2.5k will probably pay your first year if your lucky though..
I understand this post may seem a little harsh, but i'm a realist.