The W6's are dual voice coils, each coil at 6 ohms. That means additional preplanning for your wiring is required.
If you're getting the retailer to do if for you, then they should be able to figure it out. If you're doing it, it'll probably be in this fashion:
1 sub: Wire them in series for a 12 ohm load. Since you'll be bridging it the high ohm load will lower the amount of wattage taken from the amp, which is what you want since you don't want your full 800 watts going to it like a normal 4 ohm load. You'll still be getting about 250 watts RMS. I would guard against wiring each coil up to a channel unless you're sure your amp will play at mono. If for some reason you hooked it up in stereo, and then wired each coil up to the sub, then there will be problems. If you wire the coils in a parallel fashion, the sub will be pulling 3 ohms, which is more than your amp can handle in a bridged mode.
2 subs: Wire EACH sub's coils in a parallel fasion, so that each sub is now a 3 ohm load. You can then wire each up to their own channel like you wanted. You'll be getting about 300 watts RMS from each channel, which I believe is just right for these subs.
3 subs: Wire each sub's coils in a series for 12 ohms each. Then wire all the subs up in a parallel config, and it will all come out to a 4 ohms total load. Each sub will get about 250+ watts RMS.
http://www.teamrocs.com/technical/pages/connectingspeakers.htm
When you get your third sub, you can't tie them together in a chain, if you mean like series, where the wires just go on from one box to the next, because your resistance will be like 36 ohms or 9 ohms total, depending on how you wire each sub internally. You're trying to wire them in parallel, so that each sub with 12 ohms, will bud off of the common amp connection, rather than strung together. So when you get your three W6s, you'll be wiring each sub's own coils in a series fashion, then wire the whole sub in a parallel fashion.
I hope that doesn't confuse you, but hope it does help you a bit!
