Hi mate, I know where u coming from with this as it is confusing at times when ppl call it stages. Basically every time u modify ure car it shud be mapped to suit ie stage 1 I would guess is exhaust, stage 2 minor engine works like inlets, stage 3 I would say is major engine works ie cams, forging, headwork etc. Then it's stage 4 which is a major overhaul like what I've done lol supercharger n new ecu