Seems like a lot of bad blood on this thread, I can speak to my experiences (positive):
July 2017 - Matt did my e90 DocRace kit on my 2007 6MT with around 135k miles at the time, we did the turbo install, transmission refresh (seals and whatnot), all cooling system lines, wp/tstat, index 12s, starter, a bunch of other ancillaries. The car was done within the timeframe we discussed and other than a blowing a new Bosch O2 sensor everything was fine (Matt replaced the O2 at no charge per the lifetime warranty). I drove the car weekly between DC and NYC with no issues. There were a few really small things that I redid myself due to my OCD-ness, no complaints towards ZNM
March 2018 - Matt took my second n54 from stock to FBO and again general maintenance items + wp/tstat, index 12s...no issues with this car either, car was done on time as well.