Until further notice, I wouldn't fuck with anything in there. This thread was full of uncertain bullshit.
Take it from me, I can promise you with 100% certainty that one of the biggest mags has already reported no difference in output.
Until someone else can verify where the information is coming from saying there is a 2 hp difference, I'd sit tight.
I myself just searched since you bumped this thread back and I can't find anything. If I do, I'll let everyone know, and I'm sure everyone else will do the same if they hear of anything.