For those of you using Floyd Rose tremolos, I must recommend Eddie Van Halen's D-Tuna! Affixed to the E string of a Floyd, you can drop to D tuning in seconds! Easy to install and fairly simple to set-up, you can have one guitar that does the job of two! I add a Morpheous Drop Tune petal, and you can tune up for just about any song! Check them out at your local music store or buy online!