I gained power going to a shortie on the Dyno, midrange mostly, usually they end up in a loss below peak torque and gain above it for most vehicles. The tone depends on which shorty your talking, some sound like hell and are crazy loud some aren't.
The R3 is so choked off stock though, anything will be a gain be the stock cans.
Should have the new setup back from ceramic coating on Friday, I'll drop a pic here. I should qualify that a Yosh R 55 is more of a mid-length can compared to some of the super short setups on the market these days.