Quiet Storm, I am running the Simrek drive showers and have had no chalking on the drives at all. I am getting nervous about changing the drive oil myself now. I fill the oil back up through the drain plug all the way to the reservoir instead of pouring fluid in the resevoir after the fluid has reached the side plug. I just hate to have to take it to the dealer every 25 hours (pain in the a$$).

USE THE MERC OIL
 

I USE MERC OIL BOTH IN MY AO AND MY 32 SKATER. 970 HP ON BRAVO 1.36 XZ AND 1230 HP ON 1.24 #5'S I SHOW THEM NO MERCY. 125HRS ON MY XZ'S AND I FLIPPED THE GEARS WITH NO EXCESSIVE WEAR. :crazy:

About the duoprop, I know of one that is on the bottom of lake michigan. And in fact quest's boat may have been the donator before it was remotored and redrived at great expense. But I have no personal experience just responding to your question.

I have experienced the drive reservoir's filling up with fluid above 3000 rpm. I run Merc fluid. One time it was caused by a bad reservoir cap and the other time by a leaking drain plug seal. I regularly check the reservoir's to see if they are filling up at wot. If a Bravo drive is not fully sealed the drive fluid will raise and even overflow out of the reservoir.
Dan