OK if I understand you correctly
your still running that maf, but have removed the chip.
your car runs better but still has "the bog".
That is probably because you removed ONE of the devices that is leaning out the car...hence the improvement.
now if you put a stock maf on the car, and you still have a bog, that's gonna lean towards a fuel delivery issue AKA weak fuel pump.
I wish you were closer, I'd just chunk my stock air box on your car and send you out for a test drive and HOPE you came back with my parts!!!haha
because Im fairly certain that would FIX the car.
is there anyone close to you that has a stock mark 8?
borrow their air box for a test....dont open it, dont take the maf out..just bolt the whole air box in...and test
you could probably pick up a stock air box W/Meter in a salvage yard fairly cheap... most of the time they dont realize the MAF is IN there..and will sell the whole deal for 20-30 bucks...