lol, 400 to 500rwkw is a big difference is drivability and cost
My advice? R32 GTST, strip it bare, get the rust out, only put in the parts that are required to make it move and get rego, rb26, eagle rods, cp pistons, jun pump and crank snout, n1 water pump, surge tank with 044, decent valve springs, clean up of head, big cams, to4z for big power or r34 n1's for response, nismo twin plate clutch
Then lots of fuel and tyres.
Easy