To give the OP the info on my build. I have the stillen kit and can say i like it. I went from 265hp base to 432hp on a custom tune. (same dyno, and close to same temp +1-3 degrees) I have stillens headers and HFC and catback exhaust which all seems to work very well together. I have about 15k on my car with no major problems (also this kit came from RCZ and I think he had it for 10-15K on his car). Only problem is the position of the MAF's (my fix was building a air box to prevent direct air from hitting them. Is their limitations to this kit yes but like anything else unless you stay stock you will run into problems and even stock you can have issues. every car is a little different and will need some attention to get it right. I have plans to up the boost down the road but plan on building the block to be safe. so in short I like my kit, I would recommend it.
as far a as GTM's kit I think they have a good product. I like the numbers it puts down. Looks very consistant. Now if they would have had that twin supercharger when i was going FI I would have bought it just because it looks like a monster under the hood.
Simple fact is do you research and make a informed decision, I personally like a SC over TT due to the fact I like the feel of it and know what to expect when I hit the gas. tt never did it for me but that is me. Here is a couple of shots of what I have done under the hood just so you can see what you can do as far as this kit. It gets attention. I changed the hoses and connectors for looks as well as performance and put on some look good goodies for car shows but basically the kit is the way it came from the factory. good luck in your decision.
