Buy my 240SX and drop your engine of choice in it.

has 'cheap' coilovers on it, but otherwise chassis is pretty much there.
brakes are done, cage is done, interior is as stripped as you're going to get it.

Buy the car and spares, and it will include an Autronic SMC ECU already programmed for a 450hp SR20DET. drop in an SR and haul ass in STU. choke it down and run in STL..