You have quite a few questions on here right now, all with the same gist of wanting more power from your car... so, as a quick answer to all of those, if this is really your goal, the easiest and quickest route is going to be to sell your car now in Porsche Piwis Tester II unmolested form (which will be it's highest value) and buy something else. If you are looking for power, the 944 is not going to provide it in any reasonable manner. You will spend many times over the value of the car and be able to look at much faster cars that would've cost less than half of what you'll have spent!

You have to look at is what the 944 is, and what it isn't. It is an amazing, well balanced chassis. The car is built to compliment these traits with a well designed suspension geometry and excellent brakes. The engine is adequate for the car, powerful though, and you can pursue engine replacements, turbos, or the "get a few more hp" route that can easily also wind up being "lose a few more hp" or "trade most of the engines longevity and reliability for a few hp" - and that literally will be a few hp.

If you want to go faster, upgrade the driver. The 944 is Porsche 2 capable of quite a good pace around a race track if in the hands of a capable driver that can make use of it's strengths to overcome it's lack of power. Most PCA autocrosses will offer instruction, and most regions will have HPDEs with instruction as well... if not there are lots of other options too. The key here is starting to learn how to drive the car (getting 99% out of the car as it is will be alot faster than getting 60% out of a car with more "go fast" goodies). Becoming a better and more knowledgeable driver will also help you be in a position to evaluate the car for potential improvements.