... about that power loss at high RPM's....
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The reflash for powerloss is supposed to correct an overly sensitive knock sensor setting that puts the car into a cripple mode. It happens without warning and the pattern is inconsistent, but when it does, you will know because it stays that way until the car is turned off and restarted. When the problem occurs the ECU will only allow a maximum of 1/3 throttle, so it feels like you've just lost your turbo. This applies across the entire powerband, not just at high rpm. Read through the ECU reflash threads. The symptons have been described in great detail.
If you're experiencing some kind of "power loss" only at "high RPM's", and otherwise the car feels fine, you're not experiencing the power loss issue that needs the ECU reflash. You're experiencing one of the characteristics of the MS6 engine, which is falling flat on it's face at about 5500 rpm. The power drop is so severe it almost feels like a fuel cut off.
If that's what you're experiencing, you don't need the ECU reflash. From my experience, what seems to really correct that power drop is a new exhaust system. I put on a CAI 3 months ago and then a custom 3" exh last week. Since the exhaust change the engine pulls smoothly past 6000rpm. That's my experience; others may say differently.