You gonna be better off doing the install yourself if possible. A lot of the big marine places don't exactly do a proper install. They cut corners and you may not have any problems for a while but it will show up. If you really want someone to do the install for ya there are several individuals here on the forum that know how to do it correctly.

Some can install themselves, and some just "slap" it on. I have gone behind, individuals, marine dealers and shops to correct the install on electronics. I've seen things such as the wrong wires being spliced into, overloaded fuse boxes because "it's just a hot wire" or "any ground will work". Transducers mounted in the wrong are because it was the easiest place to get to, no covers where the wires enter the boat, front mounted units connected to the light wires on aluminum boats -- because some aluminum manufacturers don't run extra wiring to the front and individuals don't know how to run the proper wiring to the front. My only advice is to discuss the person you're going to get to install with your buddies and get suggestions (which is what you done with this post). There is more that goes into a proper install than can be done in a couple of hours, especially if you're planing on networking units.