Boxster S no longer immobilized but...the 295$ Dme/ignition/ecu/key+ is faulty?

[Qmulus]

Umm, I find this post extremely confusing. My impression is that the OP had a water damaged Immo/alarm module and bought a set of ECU, alarm module and key and put them in one by one until it then started once all of those components were installed. If so, that is no surprise. The immo/alarm/body control module whatever you want to call it is matched to the ECU and key. You do NOT need to replace them all if you find someone that can repair or clone the alarm/immo module.

Next, I get the impression that the engine is not responding to the throttle as expected, but the OP does not have the ability to check fault codes, so is speculating as to the problem. The only way to really know what is going on is connect to it with a scan tool. A generic scanner should get generic OBDII codes in the ECU, but it won't access manufacture specific faults. It would be better than nothing. A Durametric would be better, and a PST2 or PIWIS II the best.

If you want to see if the MAF is a possible issue, you can just disconnect it. If the car runs better (it uses throttle position and a default map to derive an assume MAF reading), then the MAF sensor is either defective, or you have an intake leak that is giving it improper readings. This is a quick "get you off the side of the road" type test, but not a test I would buy parts based on.

My advice, get the car to someone with the proper equipment to check it out or you will be spending more money needlessly.

YMMV...