HI so long time stalker, first time poster in this area.

I'm looking at buying a 98-99 VW Passat or Audi A4 with the 1.8T AEB motor and I've read a lot about how you can run K04 or Big Turbo on the stock ECU with a tune and add larger injectors/Adjustable Fuel pressure Regulator (along with FMIC/Exhaust ect). But I see a lot of people seem to run into the 5.0V MAF limmit according to their Vag-com. Basically their Turbo is flowing more air than the MAF can read. I see people run larger injectors and increase or decrease fuel pressure to account for the additional air but it seems like a tuning "gray area" once you max out the MAF. I see some people drill holes aft of the MAF to let more air in but this is "un-metered air" per the ECU and Tune.

I've read that you can try VR6 MAF's from a VW Jetta Mk 3 or 4 but would this MAF work with a Passat ECU in a "plug and play" fashion? I assume not. I see 034 motor sports makes a billet Alu MAF also but I'm not sure how they are different.

So my main questions boils down to, assume I'm running a AEB motor with a K04 get close to 15-20PSI (or where ever the MAF maxes out) what are my options if I want to run a Big Turbo on a built motor down the road? can I still incorporate the stock ECU with a tune and some kind of modified MAF? I know other people are running BT on AEB's and can't seem to find a straight answer on how they do it other than "custom tuning"..

I'm seriously contemplating buying a B5.5 PAssat or B6 A4 with a AWM motor just so I don't run into this problem down the road when I can do a Big Turbo build since that motor has a MAP and I assume helps in adding another tuning options to meter air?