Is this Variocam issue?
 

Hello, I just dyno-ed my 2001 Boxster S (146,000 km) to get a baseline for further mods (bought the ECS tuning intake system with 74mm tb and IDP plenum). Car currently has Fabspeed Maxflow and a mysterious ECU tuning that came with the car and nobody knows what it is. Anyway, looking at this dyno graph, obviously down on hp and does that business at around 5000 rpm indicate problems with Variocam? Other dyno graphs of 986 Boxster S don't have that and power rises from 5500 rpm.http://986forum.com/forums/uploads02...1694699854.jpg

Tagging along to find out. Please post your results after the intake mods too!

As the Vario Cam system is controlled by the DME, which you say has an unknown aftermarket reflash, there is absolutely no way of knowing what is causing the issue. If you really want to know, reflash it back to stock, re-dyno the car and see where you are, that is the only way you will know for sure.