Best Bravo Conversion Upgrade SURFACE style drive IF money was no object! Must run a clever style surface prop. (Must be able to rig in majority of bravo based boats)

Arneson ASD-7 bravo conversion kit
Imco SCX-4
Imco SCX-4 + Extension Box + WCM blueprinted Lower
Mercury NXT Drive
Mercury NXT Transom W/ #6 Drive
Mercury NXT Transom Upgraded Trans W/ #6 Drive + WCM blueprinted Lower

Best Bravo Conversion Upgrade SURFACE style drive on a budget, best bang for the buck.

Arneson ASD-7 bravo conversion kit (includes drive, new steering, new trim rams, new trans, new extension box, etc. sell your old parts)
Imco SCX-4
Imco SCX-4 + extension Box + WCM blueprinted Lower
Mercury NXT Drive (not bolt on, major rigging required)
Mercury NXT Transom W/ #6 Drive (not bolt on, major rigging required)
Mercury NXT Transom Upgraded Trans W/#6 Drive (not bolt on, major riggin required)

Best outdrive if money was no object building a NEW boat.

Arneson ASD-8
X-Power
Mercury #6
Mercury M8
Ilmor Indy
Konrad ACE
Imco SCX
Imco SCX-4
B-Max
Weismann Marine WSD MKII

BADAZZ!
http://www.weismann.net/Products/wsd.html

can't believe Indy and X-Power are left off the list