SAFC's are cheap and proven, you could always re-chip your stock ECU with a more aggressive map, or if you have a burner you can alter the chips yourself with a variety of ECU burning programs, here in the states the popular programs like Evilscribe, and TunerPro RT have and are gaining quite a bit of popularity as of late. You could also run a DSMlink on your car which basically gives you 99% of what a standalone is capable of but uses all your current sensors and ecu etc.
Cheers