Wow. I can't believe I didn't see this thread.
Sooo glad you got you car comoleted, I have sooo many questions.
Do you know if he changed any internals like pistons to lower compression and do you have a boost gauge and know how much psi it is running atm?
If we know these two, not hard to get a close estimate on hp, since every additional atmosphere doubles hp, 14.7 psi or 1 bar, but if they lowered the compression ratio then base engine would have less hp, and different to calculate l.
The exhaust sound sounds like how mine sounded before I had shop redo my exhaust, I couldn't hardly stand how it sounded for the 1 week I drive it.
I like the 0 drone I have now.