I haven't seen any dyno's with it, but I would assume that it is comparable to the COBB SRI...maybe a couple of hp in either direction above or below what the COBB adds.
It's a nice intake. Its HKS, so it is a good part, and I have seen it on an MS3 and it looks very good in the engine bay. Sadly, I don't have better numbers for what it actually adds, but again, I don't think it would be much higher or lower than the COBB SRI.