Hold on Adam, the stock maf is capable of making more power than that actually. Look at Grady, he made 293rwhp with the stock maf, throttle body and catback.
AND A REEEEALLY GOOOOOOOD TUNE USING THE TWEECER
The last time I checked, the O2's are ignored under WOT, and the maf is what the computer primarily reads. The O2's are for just cruising around.
You are correct on the O2s. I learned this when I began tuning my car with the TwEECer.
By the way I understood exactly where the original poster was coming from. I can't help too much with a piecemeal build up as I just saved and did a complete motor build up (bottom to top) and the H/C/I with parts already in mind - Of course after do my research. However, I did piecemeal the supporting foundation over time before my rebuild, such as exhaust, subframe, gears etc. Evaluate these guys suggestions and take it from there.
The first parts I purchased was the entire exhaust from the header on back with offroad H pipe (I wanted the classic mustang sound), then the gears. Then I tightened things up with the strut tower brace and subframe connectors and then purchased the MAF, TB and pullies. But I have the Cobra which already had the intake and heads which were good at the time for me.
Take your time before tossing out your cheddar.
Peace
Al