Need alot of help

What state do you live in? GT40P heads require the use of special headers. Ford Racing makes a nice set of GT40P Stainless steel shorty headers at Latemodel Resto for $239. You could go long tube headers but only use those if you have some serious plans for that engine with high HP. It's all personal preference as far as the way it sounds, but long tubes really drop out torque and push the HP to the higher RPMS. That's why I say they are better suited for higher HP engines. X-pipes give better HP but I never was pleased with the way X-pipes sounded. Personally I like O/R H-pipes. But if you live in a state like California, then you cannot have Offroad pipes. You must get a catted X/H-pipe. Mufflers, again, personal preferences. Here.. take a look at this site MustangExhaust.com - Blog . You may have to register but this site has been around for years and has tons of different exhaust sound files with different setups.

I'm sure someone else will chime in here. Good luck

Find out what requirements or limitations your state places on emission control equipment before you mod your car. There are some bolt on parts that will give you a nice kick and not cause problems with smog inspection. Some states are really hard on visual inspection, so anything that doesn't say Ford on it draws extra unwanted attention.

On a budget? do the junkyard upgrade...

All of the following parts will not be noticed by the smog inspectors and will not cause smog inspection problems if correctly installed.

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-$200 or so to complete the brake upgrade.

The MAF is not needed on Speed Density Mustangs made during 1986-1988 unless they have been converted to Mass Air.
94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes. *1 *2

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-$120. A must have to make the electrical system work like it should or if you have an electric fan. 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.

Aluminum driveshaft: (courtesy of shawn13) It needs to be from a 92-93-94 Aerostar AWD. It measures 45 ½” center of the front U-joint to center of the rear U-joint. You will need the U-joint, part #PUJ353 from NAPA. The Canadian NAPA pat number is 1-0134BF. It should bolt right up after the U-joint swap.
Note: This driveshaft is not an exact duplicate of the Ford Racing part. It is 3” in diameter while the Ford Racing part is 3.5” in diameter.

*1.) Metal flange adapter Ford MAF Adapters - Air Filters - Kurtz Kustomz Motorsports, Inc. KKM Buy the TR70 for $40. Or spend some time on eBay looking for one that may fit.

*2.) MAF & sensor interchange
The 94-95 Mustang 5.0 MAF & sensor is also found on:
1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.