You should be fine. Like everything else wireless, the distance is effected by building materials (wood = good, stone/concrete = not so good, metal = bad), mounting location (higher = better), and ambient electrical noise (downtown NYC = bad, South Podunk Utah = good).
Also, remember that the stuff you are installing is commercial quality equipment (unlike the cr*p that X10 sells). If the equipment didn't work in 99% of the installations, Caddx would start to lose sales in a hurry.
Not to dispute David, but for a regular residential install, you might want to first try mounting the receiver with the M1.
I have the Receiver mounted in the same box as the M1, in a wiring closet with a 200 amp panel, 1 subpanel, two video amplifiers, my Homeseer PC, an Ocelot, what looks to be about a mile of wiring, AND the incoming water line for the house. Oh, yeah - and it's in the far corner of the basement!
Works fine all the way to the other far corner of the second story of the house, through a layer of Mexican tile and a bunch of granite.
I installed in the basement and it works fine. It is next to the furnace...and has the water heater etc there as well. A lot of metal....I will do some more tests with my keyfob from the driveway so that I can see the range.
Let me restate that: If you are on the fringe of the range of the Caddx receiver, moving the receiver outside the metal can, say 10 feet or more away from the control, may increase the operational range.
At my house the Caddx receiver is in the metal can and the whole house is covered. The control is located in the basement.
GE Caddx wireless is what type of wireless. Is it secure? Does it use encryption? What frequencies does it operate on? How does it match sensors to receivers (create a link)? Can two systems interfere with each other? Are devices polled or do they periodically transmit their state?