Most of the "hard parts" are the same. They just have some different control mechanisms. Sprags will break from hard shifts that are too abrubt. You shouldn't have that problem with a stock valve body. IF you break it, my guess would be from clutch slippage, which results in heat and burning up clutch packs, which results in damaged thrust bearings and clutch baskets.
A properly modified valve body should IMO:
1. Increase clamping force of the clutches, thus increasing torque capacity of the transmission.
2. Increase the speed and firmness of shifts, but without being so fast that shifts are too harsh thus resulting in exploded sprags.
3. Increase general line pressure, This is part of the two line items above and supposedly will also result in more efficient power transmission to the wheels (less drivetrain power loss). This is one of the things that will be directly tested. (catch that, O-Guage?)
Rule number one with any auto is KEEP THE FLUID FROM BURNING UP. This has almost everything to do with the torque converter. I will experiment with a manual lock up button, and the a340e comes with a temperature sensor on the trans. It is external, so I don't see why this couldn't be used on an AW4.
From my conversations with the Jeepspeed guys, that has historically been the number one problem with the AW4 and is the primary reason why they don't use them in Jeepspeed events.
Check with me before you spend all that money at the import place. You can get all the soft parts for around $300 at a transmission parts supplier in your area. All the part numbers needed are listed in the rebuild thread.