Can one install their own avionics? For example I'm quite capable of installing a GPS / Radio (VOR / whatever)? There is nothing rocket science about it at all.
I appreciate for IFR equipment then obviously one needs to be sure it is properly inspected and tested, and of course paying for this service is fair enough. I'm thinking mainly about VFR kit, but could you install IF kit then pay for an IFR inspection (like the Radio "annual" whatever that is - cost us £150 I think and I still had the fix a problem after collecting the plane).