I agree with this wholeheartedly.
S14 is the pick of the bunch for a cost vs performance equation. Cheap, reliable, 5 speed instead of the S15 6, good engine setups stock, plenty of room for rubber and not too old. You'll be able to happily punch out 200rwkw's all day at the track and the thing will be basically stock. Add some suspension, good pads, rotors, oil cooler, tyres and you'll be laughing. No reason as to why you wouldn't be punching well under 1:40 at Winton.
They also look good, have a heap of aftermarket support and are common enough to be easy to find.