First of all get a pod filter (or easy flow stock filter) and a largish exhaust this will help it breath much better, rev easier and produce a bit more power. next I'd go the suspension, stiffer shocks neoprene bushes and pineapples to stop the rear end floating, from there you can spend lots a money on all sorts of things ECU, intercooler, turbo, cams, injectors the list go on and on