The Droid 4 came out just a few days ago. We already have root and a full on Root Utility for this device. Developer NitroGlycerine is currently working on a Droid 4 bootstrap to get ClockworkMod Recovery on this device! Early testers have reported that nandroid backups and restores are working. Before you know it we will have custom Roms for this device. Until then it is good to know ways to improve performance. The quickest and easiest way to instantly improve performance on any non vanilla Android device is to add an aftermarket launcher. Getting rid of the manufactures skin overlay is a really easy way to make your homescreen fly! Debloating is also pretty simple stuff, and is necessary to free up essential resources. Titanium backup provides an easy way to get rid of Bloat yet keep it in the background in case you need to add it back for an over the air update!
Be sure to bookmark the Roms section of the Droid4 forums and check it often for Rom releases!