Buy anything lol, GTR's are good but they come with a very expensive Tax epically R34's just ask Kingy, High Quality aftermarket parts are super expensive (Been there done that) and if not done right has great potential to bite you in the arse hard like any RB engine would. My choice of car at the moment would be Evo IX hands down. Cheap to purchase, cheap to buy parts for and handle anything you can throw at it.
My missus has given me the green light for my next project car 67 - 69 Chevy Camaro Coupe with LS9 conversion Old school car with New School running gear with a JDM style to it, will be a few years before that happens lol. Starting to research how that's gonna go i want a nice weekend cruiser with infinite Nm of torque .