Have you actually driven it, as it won't boost without load.

Reading back through, how did you solve the wastegate from being open full time and the screamer barking its nuts off?

Have you checked the spring in the wastegate? You can also check to see whether the wastegate is actuating by hooking a air line onto the bottom port of the wastegate and seeing if the plunger moves.

Also I see a Black ERST over Shoreham - is that yours? Has Red calipers and RS 7 Softlines.