I am at altitude (over 4000 feet).Before l lower backpressure, l figure l ought to increase, if possible, the air my engine is getting.

Your 993 has a healthy aftermarket following, seeing as it is the ultimate production air-cooled Porsche produced. If you are interested in specific intakes, l would personally recommend the powerflow kit at Performance Products. http://automotion.com/productpage.aspx?pid=105086&name=PowerFlow+Kit

your best bet would be to put a colt air intacke. becase the coolter the are the more hp and hp = speed

Short ram intake, cold air intake. Do you mean a Forced induction system???

There r various options for increasing air intake, & also, other measures, checks & adjustments to make in conjunction. l am not sure what ur setup is currently but l will assume it is stock.

It is clear that u r looking to modify ur mixture air as opposed to airflow into the bay for cooling purposes. Yes, a good quality air filter will help, but beyond that, u can make adjustments to ur mixture to compensate for altitude & the addition of a hi performance cold air intake would most likely prove beneficial. There r hi performance kits available for ur 993 which come complete with exhaust, headers, cold air intake box & assembly & proper filter.

Although a full high quality kit like this would run u about $2700, l think u would see the benefits u r after. You can add the airbox without modifying the exhaust system, but remeber, what comes in has to go out, & u need to balance out both the intake & output accordingly.

The 993, last of the air cooled classics. Nice choice. But l still love taking my 69 out on the twisties & hearing those Webers roar.

No, for god is sake do not put a K&N filter in that car!!!

Porsche did not leave a lot of HP on the table, & a simple drop in filter is just a waste of money & may screw up the car.

There is a good aftermarket support system for ur 993. If u want more power, think of ur intake/engine/exhaust as ONE LONG TUBE. If u increase the size at one end, you'd better be doing something either inside the engine or at least on the other end.

I'd say that perhaps a really well-designed aftermarket air box or ram-air, coupled with some good exhaust headers & mufflers is one way to go..but it wo not be cheap.

Please do not put a K&N in there, it is worthless & dyno tests have proven this time & again.

Porsche r Holy car really, but with that Godly side a devil comes with it which is mods, & repair. If u work with a porsche then u will ruin it. Its just the nature of a Porsche. When the Porsche comes home its a work of art but if u add or play around with it u ruin it, but if u get another master artist to put details then it become greater, this means u must only & only send the Porsche to a CERTIFIED Porsche dealership(repair shop) & get them to do the job for u & then nothing will go wrong wiht it after. You just need to deal with it its a Porsche is nature to be like the beautiful snorting stallion its was built like from the factoies in GERMANY. If u change some thing then in one day u will need to repair it & it will cost lots of $$$$$$$$$$$$$$$$$$$$$$$$$$$ & will do that over & over again beause it has this stray part thats not PORSCHE in it. Thats why the intake must & only be Porsche certified from the dealer only!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11