Just spoke to my buddy who works for Stillen and he told me they've just finished testing their new intake and exhaust for the stinger ( 3.3TT). The intake alone gained 15 HP at the wheels, the exhaust alone gained 18 HP, and combined they gained 26 HP. Those numbers are better than K&N and Borla. He also told me that it seems KIA has under-rated these from the factory because the baseline dyno pull was 344 WHP (370 WHP with the intake and exhaust). They should be released for sale sometime in the next couple months. I guess it pays to not rush something to market.