[mehlosTT]

AEM ems to be drivable:

Actually_ AEM's workmap that is uploaded to the EMS can be drivable with the stock MAF connected, however__ tuning it is much harder for boost level conditions unless you have the MAP sensor to read the engine load. For drivability that isn't too rich or too lean, you __still__ need a good WB-O2 so the EMS can read the signal and use O2 Feedback to keep the Air Fuel ratios fairly consistent to the 14.5:1 ish ratio for cruising.
But you will still need to learn the parameters and fine tune her as best as possible for fuel table and load tables. I am sure I have some workmaps that were on the MAF with the 450 cc injectors that runs well enough that one would not know it wasn't the stock ecu driving it..but that workmap was then result of thousands of miles in a 8 month period , of drive and tuning.

Got the cash..get the AEM ems. On a budget...get a used ECU and build the engine first..just my older guy $0.02