A guy at our field has that setup a four star with a .52 4 stroke and it flies great, I dont think it would hover , but its not meant to, but it has Plenty'O'Power...Rog
I dont know about them myself but with those funky exhaust pipes I imagine they throw the spent fuel away from the plane better so they are less messy or perhaps the unburnt fuel helps to dissolve the goo on the plane..