After a garage crashed my MY99 I am slightly paranoid. Getting a new car but want to know if its possible to disconnect a sensor or something similar to stop boost? So when a trained monkey needs to drive my car they shouldnt be able to go too fast and take anybody/anything out.

I have the same worry- i generally use somewhere that either have much faster cars to play with, or are all old people (my regular 'servicing etc' garage is a cupla old geezers, and my tuner builds F1/Indy Car engines for a living...!

Heres a way tho----

A little bit fiddly but you could disconnect the actuator rod from the wastegate (only held on with lil pin) then hold the wastegate open with a piece of wire, then you will get no boost at all.
Getting to it can be a bit of a pain, as the heatshield etc on scoobies is in the way a bit, but actually disconnecting the rod will be easy as the actuator spring on scoobies are v.weak in my experience (i got a 3dr cossie n it takes 2 people to pull the rod back on cuz the bloody springs so strong).

Make sure u wire it OPEN tho!
And do it when the engines cold if u dont wanna get burnt!

CheeRS

Steve