Still getting used to this new fangled turbo idea, so a question I would be grateful for any help on.

I changed the thermostat today. Did the following to get to it:
- Took off the induction pipes from intercooler to manifold
- Took out battery
- Took off thebreather to separator hose
- Disconnected the idle actuator, took it off the engine and moved it to one side
- Removed a small bore pipe from a little solenoid valve attached to the slam panel

Put it all back together (did front brakes as a little side line as well), and now I have huge overboost.

I have read a few other threads on the pierburg valve (the last thing I mention above?), and seems like this might cause it.

The symptoms are quite well described in other threads, but basically if you boot the car, boost goes way way up (I have a boost gauge), and the fuel cut kicks in. Driving light footed its fine, and the car was fine last time I drove it a few days ago, so definitely disturbed something I think.

Any ideas appreciated.