You might post this in the 24v forum or in the general to get a wider audience. I am pretty sure I saw one of these at the last NW BOMBers get together. The guy seemed to really like it. I also recall others recently recommending it to another propane post.
I dont have a propane system, but from what I got, they like the variable oriface stuff. Can be adjusted so 1# boost = 1 unit propane, and 30# boost = 30 units propane for example. As the boost level changes so does the propane level.
On the other hand, if you are crusing along at 70 with 5# boost do you really need the propane getting used up. Could be nice to have a system that comes on, only when you have the throttle pressed. -- Of course there is the off switch.
Anyways besides installation and mounting, I would do some research on how the different ones are adjusted, and how that translates to real world driving situations. How does this behave when I am crusing? Stop and Stop morning commute? Towing ?
Then send me email with your report so I know what to get, too!