They work EXCELLENT on V-6 and V-8 setups. They're actually quite popular, though I forget the main manufacturer of the kit (think it's ATS or something?). There are many F-bodies in El Paso, that run this setup. When I first saw it, I laughed, because I hadn't really thought about it in detail.
The main reason why some prefer this kit, is because there isn't a lot of room in a V-8 equipped F-body, or so I've been told.
I honestly don't see any difference in how the turbine should effect performance. Spool times and boost lag could be a bit higher, IMO, but I wouldn't know, as I've never ridden in one.