Someone here posted they did one from Protorque, and liked it a lot. I have not searched for it, but I'm sure you can find it. In regards to your questions:
1. I'm pretty sure it's the exact same tranny
2. The TC are probably identical. However, since the WRX is turbo, it may have a different stall speed, but the new RS is probably the same
3. See above - someone did. I am planning on one from Protorque because they are less expensive than LevelTen
4. I believe it's a swap deal. I was thinking I could get a used one from a wrecking yard, send it in, then have two. I can't really go without my car for 2-4 weeks while they do their thing...
Hope that helps!
1. I'm pretty sure it's the exact same tranny
2. The TC are probably identical. However, since the WRX is turbo, it may have a different stall speed, but the new RS is probably the same
3. See above - someone did. I am planning on one from Protorque because they are less expensive than LevelTen
4. I believe it's a swap deal. I was thinking I could get a used one from a wrecking yard, send it in, then have two. I can't really go without my car for 2-4 weeks while they do their thing...
Hope that helps!