It says replacement, you are not replacing it, simply removing it, I cannot see why you cannot take it out, send it off and arrange it to go to your avionics engineer, then he can fit it on one visit as opposed to two, just check with him if he is happy for you to remove it.
As for connections, as said most light stuff just fits into a tray, the plugs etc are all part of the said tray and as such are simply racked.