You would probably have a large problem with the positive ground. Reverse polarity destroys LED's and that unit seems to be based on led technology. If you could isolate the unit from the frame you might get away with it??? but expensive if you make a mistake! I read somewhere that the frames of positive grounded vehicles dont rust....wonder if there is any truth to that.
Just talked to Trail Tech and they said it shouldn't be a problem , just run the connections directly to the battery rather than frame earth. They said the board inside is isolated from the case so blowing it shouldn't be a problem . I'll let you guys know how it goes.