Here we go with the safer, 'traditional' method of performance enhancement. I advise you to read the entire recipe before changing anything, just to understand what will be happening. These steps do not need to be performed at the same time; if you must do them at seperate times I suggest doing them in the order listed.
If increasing performance is your desire, the first thing you ought to change is the computer. In fact, if you make only one change to your car this should be it. The Mopar Performance computer increases your maximum boost pressure, plus it eliminates the 'peak boost for only 10 seconds' and 'max boost only after 3000rpm' features. The computers can be purchased through most Chrysler/Dodge dealers for somewhere between $150 and $300 and installation is a simple 5-minute operation. Back when first introduced, the MP computers claimed to drop a full second off the 1/4 mile ET of your car. With the right car and the right driver, this might be possible; in the real world it is safe to expect an ET drop of .5-.7 seconds.
At this point, a certain topic needs to be addressed: fuel injectors. There are some people who would have you believe that you need to go out and install bigger injectors when the stock computer is replaced with the MP model. This is simply not true. The MP computer has been programmed to use the stock injectors; installing larger ones will only give you worse fuel mileage, poorer idle characteristics, and less power. So unless you make major mechanical changes to your engine such as a ported head, hotter cam, oversize valves, and so on (and you won't make those mods with recipe A) then save your money and your gas: leave the injectors alone. I ran my Shelby Charger for two years with all the mods featured in recipe A and I kept using my factory injectors. Nothing bad ever happened, I got great fuel mileage, and that engine ran perfectly with 150,000 unrebuilt miles on it (including the original turbo). Enough said.
One thing you may want to change, though, are your spark plugs. When I bought the MP computer for my TurboII Omni, a note was tucked in with it that recommended going two temp ranges colder, from a Champion RN12YC to an RN9YC. I'd pass this tip on to you and advise doing the same. (In case you are curious, you can take this one step futher: the Super60 engine which dynoed at 305 HP and 315 lb-ft was using R6YC plugs at the time, gapped to .025". Note, however, that these plugs were used only while on the dyno during long stretches of WOT operation. I would recommend sticking to RN9YCs on the street to avoid fouling the plugs.)
Now that you have the MP computer, the next logical change would be to install a free-flow air filter. K&N makes excellent hi-flow filters for this very purpose. If the stealth 'stock' look is important, or if money is a big concern, then a drop-in replacement will suffice; it would cost around $30 and installs in only a minute or two.
If you have a little more money to spend, and if you don't mind having a modification visible to anyone who looks underhood, I suggest installing a K&N cone filter instead. You may have to get creative in order to hook it up to the air inlet hose, but the results will be worth it. If you decide to do this, exposing the filter to outside air (rather than hot underhood air) is of prime importance - colder intake air gives better performance. Also, be careful not to locate the filter where it may routinely get wet. The cone filter option may cost a little more than the drop-in replacement filter; the exact cost depends on the filter you select and how you mount it. Even so, I couldn't see it costing more than $60 at the very worst.
After the computer and filter are in place, I would next suggest opening up the exhaust system. On my car, I chose to leave the catalytic converter in place. The factory pipe in front of the converter is 2.5" and is smoothly bent, but after the cat it drops to 1 7/8" out to the rear of the car. I decided to go for the best blend of economy and performance: 2.25" smooth-bent pipe from the cat back. I also did not install a muffler, choosing instead to just run the pipe to the bumper.
Why did I choose 2.25" pipe? Because on my car (a Shelby Charger) space was kinda tight around the gas tank. I could have squoze in 2.5" pipe but decided that 2.25" was sufficient for my needs. On larger cars (such as the Lancer or even the Daytona) it may be easier to install larger pipe. NOTE: I, like many people, was under the misconception that turbos do need some amount of backpressure to function properly. I have learned that this is not the case. So when it comes time to decide how large your exhaust pipe should be, I now say this: go as big as you want to. If 3" pipe fits and you've got the money, use it - it will provide the best performance.
Why did I not use a muffler? I was at first thinking of going with a good free-flow muffler. But I realized that the muffler alone might cost near $100; at the time I had no idea which muffler was the 'good' one. Also, all the muffler ads show how their muffler flows "almost as good as a straight pipe" and that's when it hit me: if a pipe flows better and it is also cheaper, how can I lose?
If you are worried about the noise, don't be. Yes, it is a bit louder but once the car is warmed up the difference is slight. (Remember, I'm still running a cat.) The most notable difference is at cold idle, where it has a nice sounding, throaty burble--louder but authoritative. Wide-open throttle is no big deal; the sound is just a rush of air. You see, the turbo takes a lot of starch out of the exhaust note so we can get away with it, even in strict 'noise ordinance' townships. Trust me, it is nowhere near as loud as a V8 with Cherry Bombs, nor does it sound like a farting bumblebee like all those Hondas and other imports with tiny displacement engines.
But some of you out there are no doubt wondering: what if I need to run a muffler? Which one should I choose? The hands-down winner as tested by many serious 2.2/2.5 tuners has proven to be the Dynomax Race Magnum. Shaped like glasspacks, these things are available in 2.5" and 3" pipe diameter. Best of all, aftermarket performance houses (such as Summit Racing Equipment) offer them for around $35 each. A steal if you ask me.
By now you must be curious: how much? In my case, this custom exhaust work only cost me $50 installed. I had made friends with the manager of an exhaust shop so he cuts me killer deals. (Two years later, he only charged $30 to do the same thing to the Omni! I recommend you make friends with a competent muffler shop in your area.) Your cost may be just a bit more but shopping around for price estimates will help keep the cost down. Important note if you decide not to use manderel-bent pipe: when you have the shop bend your pipe, tell them to use a bigger shoe so as to prevent the pipe from crimping as it bends. The diameter will still decrease a bit (this isn't quite as good as mandrel bending) but the lack of crimps will help cut down on backpressure-creating turbulence.
Well, that's it for Recipe A. With all three mods performed, we are talking a realistic price of $220-$450. This is affordable even for a starving college student, which I was at the time I did this to my Shelby Charger. Overall results should realistically chop about .8-1.0 seconds off your ET, the car's driveability will be completely unaffected, and you'll still get decent fuel mileage (unless you floor it from every stoplight in town). Not bad for a few simple, external mods.
Modified 9/14/07.