Chemical guys? What are those? 

Mudder stuff sounds interesting, can anyone be more specific on the name of it so it can be googled?

Re. the foam cannon, we've used them for a couple of years now. Bought an extra short wand for the pressure washer so the thing isn't so heavy hanging on the end of a 36"+ wand. I have found that the cannons do need to be rinsed well with clear water after use. Rinsed by running them on the pressure washer. Otherwise I had the little venturi assy inside the mixer get hopelessly plugged. Might depend on what soap you use. We use different kinds. Sometimes a h.d. pink colored stuff from Hotsy supplier (we don't have Hotsy washer), or just plain soap/wax stuff that might be on sale @ Farm & Fleet.

As another poster said, make sure you get an extra bottle or 2 because the threads on the neck are very brittle it seems. Also, we use an extra bottle for just the clear water rinse for the cannon.

Re. the car covered with foam in the OP, I'd be interested in what was used for soap there. I've never seen that type of coverage. Notice the long stands of foam dangling from the front air dam. We get good coverage, and we use 100% softened water, but still that photo has unbelievably thick soap coverage. Anyone else get coverage like that?