Free Modifications

Yes, that's right. This emissions-diluting relic from the early 1970's energy crisis came as standard equipment on 1995 Mustang GT's. Many owners remove the smog pump and piping to gain some underhood space and shed 10lb of weight over the front wheels. Here's the link to an excellent article detailing the removal of the smog pump equipment on a '94-'95 Mustang:

'94-'95 Mustang GT 5.0 HO Smog System Removal

I removed the smog pump according to the instructions and I was amazed at the extra space that was created on the passenger side of the engine bay. This made changing the spark plugs on that side so much easier. Another positive effect of removing the smog pump was that the exhaust stopped backfiring when lifting off the throttle. A third positive effect may be a slight increase in horsepower, since the engine will have one belt-driven accessory less to apply parasitic drag.
With the smog pump out of the way, the stock drivebelt (104.5" long) can no longer be used unless you install a smog pump eliminator pulley. Those who like a bit of underhood bling can purchase a billet aluminium pulley and install it. Alternatively, you can forgo the pulley and use a shorter 90.2" drivebelt instead. I chose the latter option using drivebelt part no. 6PK2290 and modified the belt routing (right).

This is another one of those pesky emissions-diluting relics from the early 1970's that was installed as standard equipment on 1995 Mustang GT's, and this too can be consigned to the scrapheap. Removing the EGR valve from between the intake and exhaust manifolds creates even more underhood space and makes a small addition to the vehicle's weight-reducing diet.
The only problem is that it's connected to the engine's wiring harness so removing it can cause the "check engine" light in the instrument panel to switch on. This can be overcome by plugging in an EGR eliminator simulator. This device fools the engine computer into thinking that the EGR valve is still in place so the result is the "check engine" light stays off.
I removed my EGR valve and installed an EGR eliminator simulator that I bought from ebay. I also fabricated my own EGR block off plate for the intake manifold, and added a threaded bung to the EGR opening of the exhaust manifold (right).

The elephant trunk shaped pipe (right) that goes through the passenger side fenderwell and is attached to the air filter housing narrows down to just 60mm in diameter. It's designed to reduce intake noise but it also chokes off the air supply to the engine, so removing it allows the engine to breathe a little easier. This article shows how it's done:

Removing the air silencer

The stock MAF sensor has a mesh screen to protect it from foreign material but this screen also reduces the cross-sectional area for air to pass through the MAF sensor housing into the engine. The screen can be removed easily by carefully dismantling the plastic air filter housing assembly.
I removed both of these items and there was a noticeable improvement in throttle response. Dyno testing has shown that removing the air silencer and MAF mesh screen can produce a 5rwhp gain in an otherwise stock Mustang 5.0L GT. A great no-cost mod!