Fitting well provided it's signed off by your spanners man (& done by him I'd suggest) then I see few issues there
Pause and take a breath there... If the installation requires the spanner man to sign it out (or, into the plane), he'll probably be looking for an approval of an STC nature. Do not assume that to be insignificant.
There are requirements for function, electrical load, interference with aircraft systems and security in the cabin, for which a finding of design compliance may need to be made by a competent authority.
Have a talk to spanner man first with your plans, before you spend money. If the plane does not belong to you, include the owner in your talk with spanner man.