Yeah they are cheaper than most and it may come to that but I was hoping there was a way to mechanically "trick" the wastegates to allow more boost.

I bet you can bleed off a bit of the boost pressure sent to the ecu with an accurate regulator. I think even though the ECU would not be aware of the actual boost pressure it would still add fuel because the mass air sensors would know there was more air being added. This would require a boost guage obviously to avoid detonation from overboost.

Does anyone use alcohol injection to prevent detonation from high boost pressures yet? That would be the next step.

My old Buick Grand National started out with running 14psi (245HP) back in 1987 and now we're all running 28psi (600HP) with no trouble. My point being, these X5's could be ridiculously fast with a little tinkering.