JKM,
If you have a direct-drive A4 your choices are limited. Most of the props listed above just plain wouldn't work (they don't make them for small enough shafts, or small enough diameter, or you can't dial the pitch down small enough) for us. For our '75 E32 with a dd A4, we put a 12" two-blade feathering maxprop on last spring and have liked it. A cheaper option is the 3-blade fixed prop offered by Indigo (
www.atomic4.com), which I've heard good things about, but we wanted something with less drag.
- Cory Bolton