Hi there,
You can fit a NeoVVL engine to it, you could either go SR20VE or SR16VE (2.0 or 1.6). both VVL engines have the same physical dimentions on the engine and use the same gearbox.
You would need to change the Wiring Loom, ECU, and Gearbox and driveshafts for it to work mate. Not an extremly hard thing to do.