tmmorris
I am responding without reference to current price lists, but to install a slaved HSI you need
- the HSI itself, e.g. KI525A
- the fluxgate magnetometer assembly, e.g. KM112
- remote directional gyro, e.g. KG102A
- various bits e.g. auto/manual switch/meter (KA51B)
- installation of the whole thing
- possible approvals from the CAA
You can contact your local avionics show for a quote but you will need a coffee beforehand, and another one afterwards
This stuff is mostly early 1980s but is still current fit in higher end brand new planes.
I don't believe you will get any change from £10k. There are far cheaper alternatives available for U.S. experimental category planes...