its a very nice looking piece of hardware. I didnt have the tools so got it installed - about 3 hours according to the workshop. paired with a stage 2 034 tune, it sounds great. it was actually a bit too loud for me in dynamic mode so I turned off the soundaktor with OBDeleven, and now its perfect. in comfort you barely notice any difference, and in dynamic the extra sound depth and crackles are amazing. it used to annoy me that C43s sounded that little bit more aggressive in comparison, but that isnt the case anymore. I dont have any tinny sounding vibrations - which can happen with some cats.
performance wise, its not a massive step up from stage 1 if you already have an intercooler and intake. its a prerequisite for stage 3, which is something I will get around to some day, but if you dont ever plan on going that far its a questionable investment for performance alone. I am running the stock exhaust so I dont know what difference it would make to an aftermarket one sound wise.
one thing that I wasnt expecting, the first run after installation when it heats up some of the chemicals from the heat wrap will burn off - which I know now is completely normal - but it smells like burning plastic. you just need to put your aircon on recirculation for a while until it burns off - only took 1-2 drives of the car for me.
also since this is my daily driver, from a roadworthiness perspective the downpipe has an EU4 200cpsi cat, and I have not noticed any obvious change in smell leaving the car running in the garage for a few minutes, EU6 300cpsi cats will set you back at least another grand, and a catless would obviously stink and be illegal - so this was the middle ground that worked for me.
I also didnt get any CEL driving around in stage 1 for at least 1/2 a day. I would assume most people who fit this would have a mechanism to clear faults, but the less often the better I guess. once you go to stage 2 the CEL is supressed, so it doesnt matter.