Picked up the Vance & Hines Twin Slash Staggers, a K&N filter, and the V&H FuelPak. Took 3-4 hours to put it all together, and the hardest part IMHO was getting the damned battery tray back in. Didn't need to remove the tank to install the fuelpak wiring, just removed the two bolts and lifted it enough to get my hands in to unplug the injectors and reach the throttle position sensor wire.
Much louder than I expected, but I love it. Acceleration is smooth and vastly improved over stock. At idle there's a nice low 'wubwubwub' but any more RPM's than idle and everyone's gonna hear it coming.
Waiting to see what this does to my gas mileage, from what I've read I can expect to lose 5-6mpg, but honestly this combo of upgrades have made this bike even more fun than it already was.