Thanks for the info all..
I replaced all the plugs, however still had a cylinder 6 misfire. Swapped out the coil - Bingo!
I'm just running the Sport ST and so far so good... I did notice it holds gears a lot longer when backing off boost in 'D'.. As in, on the standard map, if I floor it and release, it's quick to shuffle into a cruising gear (5th or 6th), however now, it'll hold 3rd or 4th (at high revs) after I've backed off completely (rolling) and eventually (5-8 seconds) bump up a gear or two. Normal??
I only had a chance to give it two quick runs, so will see how it goes tomorrow.