That's definitely a k20a2 in there. Wonder who did that swap.
Yes, it's got slightly more horsepower than the civic si, and the si tranny is there because it has an LSD, so if you have to end up getting a tranny, get another si transmission
the k20a2 doesn't have dual balance shafts on the oil pump, so it has 4 more horsepower, and revs a little faster thanks to less weight to turn on an instant.