First off thank you for any help and taking time look this over. i have a 2010 camaro with a l99 we converted to ls3 we also added cold air, long tubes and phastech stage 3 cam, ported/polished heads and completely redone rotating assembly (.030) the engine builder told me all he could find was the truck pistons which were almost identical to the car pistons so i went with it. this is my first time tuning although i am a master tech with solid engine knowledge its uncharted water for me so i am naturally cautious/scared. we installed the engine and i put the attached tune into the vcm (followed Tuning School Procedure) the engine sounded good and was strong, we drove the car 400 miles and i was doing the first oil change and decided to tweak the tune ,All I Did Was Change The idle timing from 20 to 22 at idle and the engine would barley start (had to hit gas pedal) instantly i heard some knock so i loaded the original tune back (attached) and started it up. the knocking got real bad real quick so i turned off the engine and bore scoped all cylinders to find the #2 piston completely missing the ring stuck in a valve and sleeve cracked, i haven't disassembled it yet but looks like the piston grenaded. i know i had good oil pressure and at most the fuel trims were + 10 At Idle (both banks) with a afr of roughly 15 @ idle maybe 16 tops (WB on Opposite Bank ) there was little to no KR but im wondering if the pinging from the long tubes was distorting it. any way wondering if a more experienced tuner can look at this and let me know if there is something completely off to warrant the piston explosion to be my fault. THANKS