You need to address the DAL and the WGDC, that is most likely where the KR is coming from. Go back to the LNF guide thread and start there this thread is a decent start
http://www.hptuners.com/forum/showth...F-Tuning-Guide although his DAL is a little high iirc that was when hptuners did not have as many tables available as they do now. 255 seems to be the highest most get before no changes are noticed, so starting around 235-240 in the high load areas is not a bad choice.
I'd also stick with the OE ACdelco's plugs there isn't really a reason to go step colder on a stock turbo or even a slightly larger turbo.