I'm actually doing all the work myself. The only thing I haven't done in the basement was the drywall, which I subbed out and actually wiring up the breaker box. I ran all the high voltage, but had no desire to get anywhere near that thing.
I would definitely recommend doing it yourself. It's actually a piece of cake and there are enough of us around here that can help along the way. You're going to save a ton of money. I would however, recommend subbing out the drywall or at the very least, the finishing aspect.
If I remember correctly, my theater was $3,600 for the drywall. That was Type-X double layer and the finishing. I supplied and applied the green glue. I let them do whatever they wanted in the rest of the basement, but I supervised every aspect of the theater drywall. I made them very aware of that before I signed the contract.
I had them specify fastener type and length, along with the fact that they were going to wait while I applied the green glue to each piece. I would definitely get that all in writing. I also checked to make sure they actually showed up with the correct fasteners.
I looked back through my invoices and it looks like I bought a total of 230 IB-1 clips and 39 IB-3 clips. I have a bunch of IB-3 clips left over though. I'd have to look in my box and see if I have any IB-1 clips left, but if I remember correctly, it was close.
They are a piece of cake to install. I have a few recommendations for you though.
1. Rip a 2 x 4 the height of the room. Figure out where your clips go vertically, and then mark the 2 x 4. That way you can just carry that around the room and mark all the other locations. Or, better yet, buy a laser. I wish I would have bought one of these things months ago. I think I'd be done by now.
I would also recommend a tripod because the clip they give you sucks.
2. When attaching the clips to the wall, use deck screws. Don't use normal wood screws that you find in the fastener isle. The end up stripping out or snapping off. Here is what I used. I think I went with 2", but can't remember.