Good questions,

Topgears results were fantastic, i think the engines are similar and im only up about 25Kw on his carb, non intercooled setup.
Im using a Motec M800 but im not using any special fuctions on it at the moment. The reason i went with the m800 is it can control 8 injectors sequentialy, and i`ll need this for the bike headed engine. Any cheap ECU would do what im doing with this engine. The only thing ive set up a little diferently is MAP over TPS for the load axis. The bigger cam almost made this a must.
With the E85 and intercooling it likes about 3 degrees more timing than the 18deg that Topgear could use (21deg at peak torque).
Ive never put a blowby guage on it, im actually shopping around for one ATM.
It seems ok. It`s not pushing oil out. But i`d like to know blowby CFM.

Im looking into the power falling off fairly fast. The data shows the boost is still there and ign timing is good. I think it could be one of three things. The cam choice, weak valvesprings or the dump pipe where it joins the turbo. This pipe doesnt alow a smooth conversion of the waistgate gasses to the main exhaust flow. its bad enough to make boost creep a problem from about 5.500rpm.
Fixing that will be my next job. Im less inclind to think its the valve springs as power would probably fall alot faster than it is.
And yes, the restrictor is not coming into play.