I think it will all be sorted out in due time. The lag, bog, black smoke and unburnt fuel
smell are no accident. It's from setting the mixture rich.... Mine was running at 11.1:1. Ignition retard is also involved in that bog/low torque output setup and sends unburnt fuel into the exhaust. When a car runs like that, it runs cool and without detonation. It's "safe", but is low on power and has poor throttle response. If you leaned it out to 12.5:1 and advanced the timing 5 degrees or so, the car would spring to life and be a lot closer to emissions targets, make more power, have better throttle repsponse and get better gas mileage. Independant tuners are tuning the car this way and having good results. Like RCZ, right? What that tells me is Stillen either has evidence that damage is occuring under high rpm + high boost conditions when mixture is leaned out and timing is advanced, or they just suspect it and are afraid to lean it out for fear that someones engine is going to blow up and they get blamed. That becomes a
PR disaster. If someone 's supercharged Z blows up with a stillen kit, but a tune from someone else, they can easily deflect blame and say it was improper tuning and say that none of the cars that they have tuned have had problems.