Stage 1 map. Best bang for buck. (240bhp)
Loads of tuners to chose from. Do a search on here for options.
If you need more power after stage 1, stage 2 requires a sports cat. (260bhp)
If stage 2 bores you, stage 2+ can be had with a HPFP and an intake. (280bhp)
Dont forget brakes, suspension and related handling mods