Thanks for the write up! Definitely helpful. I'm not sure if I will have the opportunity to hear both of the two though in person unfortunately.I have had some experience with invidia. Not on my personal car but heard the invidia (q300) in a car during a drive in with a local guy here. The invidia was on a wrx and I have an STi, but they will sound the same on both cars. My impression with the invidia was that it was excellent quality. It was constructed beautifully and I was told that the fit was spot on. It seemed just slightly too loud for my taste. But overall, it is an exceptional exhaust system and would highly recommend it to anyone.
As far as the turboxs it was exactly what I was looking for. It is not that loud at idle, but you certainly notice a deeper tone to it. Same with cruising around, and I have basically no drone at all. When you go wide open throttle you can hear a big difference. But again, it is not obnoxious. The build and material quality is top notch and it fit into place with very little effort. I am extremely happy with it and think it looks and sounds awesome. Fills in the back of the bumper nicely. I would definitely recommend this exhaust.
Overall recommendation though is to hear them both in person if you can. I do kind of like the fact that less people have my exhaust than the invidia, but that's kind of a stupid thing to like. Invidia is popular for a reason. Whatever you end up going with I would recommend getting aftermarket exhaust hangers. Also, fasttuningproducts gave me a sweet deal.