You mentioned a 1/4 turn throttle in the original post. I wouldn't consider that a good bang for you buck performance part. Because it doesn't actually give you any additional performance. It just makes the throttle turn shorter. It's nice for some people but it definitely isn't necessary.
As everyone has said, Lloydz Air Filter, ATS (Timing Wheel), good exhaust, PCV or other fuel tuner and a good professional tune. From what I can tell the exhaust can actually alter your power figures quite a bit. I have the RPW's on my bike and while I love the sound (they are loud) they make quite a bit less power than the D&D's that are on my Dad's XCT and my brother Vision.
2011 Cross Country
-Cee Baileys Windshield & Lowers. Victory Lower Bag Rails, Driver And Passenger Backrests.
-RPW Exhaust, Lloydz Air Filter, VM1 Cams, ATS (Timing Wheel), 1/4 turn throttle & IAV. PCV with Custom Tune by Coweta Customs.
105.2 HP & 127 Ft-Lbs on a Dynostar (Eddy Current) Dyno.