I've only used Allen's tunes and had 100% success with him. I never have driveability problems or SES lights. I can't remember that article but I think Allen sent in a mail order tune and the other guy got to tune on site. The on site tune should have been better, but you saw the results. Go will Allen Nelson, you won't be dissapointed.
2006 Superior Blue Trailblazer SS AWD, Stock as a rock
Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).
Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning