In the unhappy case of finding marks on the pistons, I will have to change them. As the OEM ones cost about the same as Je pistons, I'm thinking of upgrading them. My OEM compression is 10.5 (highest of all, being my AXX was the first TFSI engine code). Je has CR of 8.5:1, 9.5:1 and 10.25:1 with bore 82.5(OEM), 83 and 83.5. I will not go with 8.5 but wouldn't know what to choose between 9.5 and 10.25 (they also make custom so I'd go a little bit lower but not too low). Also, in terms of bore, should I go 83 just to be sure ? (even if the actual diameter is still closer to 82.5). How does lowering the compression affect everything on this engine ? (updated REVO software ?, engine temps....)