The original kit manufacturer was Spoolin who droped out long ago, then Flyinprotege called it quits, then there sister compnay BEGI stoped production aswell I believe. The remaing kits are MAM, Wagner, and Hiboost. I am not sure of any others.
As for what you have heard, well, I have lived it. I had one of the first Turboed 3rd gen proteges. #7 if I recall

. That was back in 2002 and I have been on this board since it began. The reality is that 90% of the boost Proteges out there are simply not reliable as daily drivers. Most people that do that level of mod ( and trust me they rarely post about it) tend to regret it with these cars. Atleast 50% of the member here that at one time had a turbo protege, no longer have that car. I have yet to see someone run the needed boost on a P5 to get 200 whp and have that car:
1. hold up for even a year/12,000 miles
2. not need constant retweaking or new parts to fix short comings.
Not to mention, most everyone underestimates the tuning needed to make a good EM. almost no one here has the experience to custom tune a car as needed to run 200 whp on these cars. Hell, most people that invest that deaply in the car, never even get it running solidly for a month before its either back under the knife or sold.
This car simply will not be a daily drive once boosted to that level. Again there is nothing on the car that was built to handle that power. Even if you get it to 200 whp, its becomes overly useless as the car is 1 wheel drive. With a really good limited slip dif, the power is wasted with tire spin and torque steer.
2.