[The Radium King]

I think most people run with the oem tune (or aftermarket) after intake/exhaust changes. the fact is, with intake/exhaust improvements your car breathes easier but the additional airflow is still detected by the maf and the maps in the ecu have a large enough range to allow the ecu to fuel properly.

I think a 3.4 x51 map is a good solution but don't know if it would work. it's something i was hoping to examine myself. as previously stated, you would need the bigger maf housing so that the ecu can extrapolate the airflow correctly (cayman housing would work as it is the same diameter as a 996, as well as work with a 987 airbox if you go that route, and further reduce intake restriction). don't know about vins - im not familiar enough with my pst2 to make that statement. I do know that you can make a 996 ecu talk with a 986 alarm module, gauge cluster, abs, etc., so worst case scenario is that you replace your 986 ecu with a 996 unit as well so that it will accept the new tune.

edit to add: a quick trip to ebay shows the cheapest 996 dme sitting around $200, which might make a $700 custom tune seem not as expensive. again, you might be able to push a 996 tune onto a 996 dme without aggravating the clu, etc., but I can't say for certain. holyoak would know.