What are the differences between the 2? I can visually see some but does anyone have full tech specs/ results?

 

Looks like they bore out/replace the opening and put a larger flap in it.

 

The opening is bored out on both sides. I don't recall where I found it, but the ID is obviously larger. (May have been on a Boxter thread?) The flap is the same size (appears to me). The butterfly shaft also has extra metal shaved off. I assume the reduced mass allows for a faster reaction to the throttle inputs.

I bought mine about 3 weeks ago. As of then, RSS had not done any dyno testing on a 996.