I think you're confusing the gt4088R with the non-R journal bearing turbo there Mike. I'm pretty sure Jamie has never had a 4088R, both his were plain 4088s. You can't really make comparisons between the housings of the two types because so much is different between them.
I'm wondering if your ECU needs remapping for the new turbo. I know you said it's self-mapping but how well is it managing the ignition timing really?
Can the V Pro really remap itself for a different turbo? It just seems unlikely to me, but I'm no expert.
I don't believe the stock cams are a problem with the PHR1 turbo as it ran out power just the same on my car, which has 264/264 cams.