Don't use an EBC on TTs, they get confused and you end up with massive boost spikes as the secondary comes in, it'll eventually pop...
Rev A/B/C are mostly the same, RevD is the facelift with the newer headlights and the smarter ECU (blackout cluster, clear side indicators, etc)
The high fuel consumption was as a result of having a different exhaust (dealer fitted in japan , it'd had these issues a long time) messing with the air metering (don't ask, complicated) and yes also the overboosting.
They run a 64L tank, I've seen around 350L from a tank but I haven't done any long distance drivign since swapping ECUs, I'm getting around 11.2l/100km now around town by my calculations.
If fuel economy is a concern, don't buy a TT