Installing a Non TSO AV30 in a 415 C

I installed the non tso AV30 in my coupe, but then I am the IA that does the annuals as well, so I don't have to worry about it not passing.

I'm sure the original list didn't include a cd player, either. So, do you have to have a TSO'd CD PLAYER to be able to install one without an STC? I'm up to HERE with the FAA regulations and the government's tendency to limit our ability to make choices for ourselves! I'm going to install a non-TSO Garmin G5 PFD in my 'Coupe. Let them say what they will! This is a real SORE point for me! Go for it, Morris!!

This my only concern now. I have a reliable A&P willing to work with me but my long time IA went west last year. Probably will spend the extra $$ just to avoid a future problem.

The fly in the ointment is finding an AP(IA) to sign off on it, both for the installation and subsequent annuals.

I read where there is no TSO requirement for instruments not required on the orignal aircraft type certificate, in my case A718. There is a no STC  version of the AV30 that is $400 cheaper than the certified version. If you do not replace the required airspeed indicator and altimeter then is legal to install the non STC version of the AV30? Sounds almost to good to be true . Just wonder if anyone has thoughts on such a bold idear?