[Dave at Pelican Parts]

Options:
- 914 gearbox. Least expensive; you already have one. Can throw some $$ at it to strengthen and/or re-gear.
- 915 gearbox (from a 72-86 911). More expensive, but well understood. Ring and pinion flip needed, minimal machining required for that. New gear shift linkage and revised clutch linkage required. Mounts must be fabricated, or use Wevo's tail cone for mounts and shift linkage. More durable.
- 930 gearbox (from a ~77-86 911 Turbo). Only has four gears, but they're tall. Very durable. More expensive to buy, and requires more machining to flip the ring and pinion. Mounting and shifting solutions need to be fabricated.
- G50 gearbox (88-94 911). Must be flipped upside-down to run "backwards", I think. Requires modification to the oiling and breather setups. Better shifting than the above due to revised synchro design. More durable than the 915; not sure about the 930. Mounting and linkage must be fabricated.
- Boxster gearbox. Unknown torque capacity, a fair amount of modification to the chassis required to mount it. Starter fits on the "wrong" side, so provision must be made for that. Unknown clutch requirements. Evidently Boxster cable-shifter works well in a 914.

Take a look at the Renegade Hybrids site; they pretty much have this stuff well worked out.

--DD