I don't have drive showers yet, but Iam looking at these, no drilling and seems like better cooling, plus they are outside of the cav. plate. I've got some maximus's coming from BBlades, and I think these are the way to go.......?

http://www.driveshowers.com/

I have these drive showers and I love them. I have them on the old style bravo 1 drives with the 1 inch prop shaft. Also, Maximus props. 600 hp supercharged engines on a 12,000lb Cigarette. Have not broke them yet. No more Chalk build up. Upper Gears look clean every season. Nevertheless, my prop shaft is starting to look a little twisted.