Beth has the Drummer on her X12Bcg, and while we've bought the ECM and K&N filter, we haven't put them on yet because we haven't had the time to get to Harley to get the TPS reset. Right now she feels it's definitely not quicker, and maybe even a touch slower. We don't expect that to be the case once the new goodies are on.
I will say there's a bit of bluing on the pipes near the heads which I'm not crazy about, and she definitely doesn't wring it's neck on a consistent basis. Hopefully that will also change.
I have to say though, $400+ for the Drummer, and about $250 for the ECM and filter... why not finish the job and do it right?