MASS air conversion instructions from
http://www.stangnet.com/tech/maf/massairconversion.html FREE
A9L computer from junkyard $100-$150
70MM MAF from 94-95 Mustang GT - $40-$70
MASS Air wiring harness kit $30-$85
The whole thing is probably less than $300 using junkyard parts.
On a budget? do the junkyard upgrade...
Gears - 87-88 T-Bird Turbo Coupe rear axle - disc brakes and 3.55 or 3.73 gears in one package for $125-$300. Add another $100 or so to complete the brake upgrade.
94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 58 MM on regular stangs built prior to 94. You need a $25-$35 flange adapter from Pro-M to fit the stock air ducting. Wiring plugs right in with no changes.
95-97 Ford Explorer intake manifold & throttle body $150-$300. The intake manifold flows 220 CFM +, much better than stock. Throttle body is 65 MM, bigger than the 60 MM on stock stangs. I got a 96 with EGR passages that match the stock setup, so my smog gear works just like factory. You’ll need a 65 MM EGR spacer & new gaskets for $65-$90 so you have a place to mount the EGR & throttle linkage.
3G alternator from 94-95 Mustangs or other Ford. $20-$80. A must have to make the electrical system work like it should. You’ll need a 4 gauge power wire and a 125-135 amp fuse to go with it about $15- $30.
Lincoln MK VIII electric fan -$40-$160. Free up some HP by not having to drive the stock fan. The 3G alternator upgrade is a must have prerequisite before you do the MK VIII fan. You won’t have enough electrical power if you don’t do the 3G upgrade.