Again, thanks for the comments
Bit more progress last night with improving boost control... I wont bore everybody with the details (unless anybody wants to know, in which case more than happy to share what I've done).
To answer the question of expected power?
I'm not really sure. I've been so close to 200 that I guess I'll need to break that at some point as a bit of a target.
It feels really good with the current set up and even after that I'm looking into hybridising the cold side so plenty of avenues to explore even with the current turbo.
Bear in mind it has to be a reliable daily too though :P