the starter 
And true duals to expose it. Here's jeffj's list from a thread awhile back
After Market Parts:
Legend Air Ride - 2404-1001
Freedom Exhaust
Power Commander - 1020-0001
Chrome Stabilizer Linkage - 16308
Shifter Lever - 1811-2124
4 Windshields from Fast Aire
Genuine Harley-Davidson Parts:
SE High Flow - 29773-02
Chrome High Performance Starter 1.4 - 31559-99
Chrome Master Cylinder - 41777-05A
9.5" Windshield - 58301-96
Billet License Plate - 60060-04
Chrome Inner Primary - 60739-01
Braided Crossover Fuel Line - 63698-02
HID Headlamp - 68094-06
Electronic Compass - 74502-05
Cylinder Base Collar - 32753-01
Touring Oil Vent Line - 33111-02
Stealth Footpegs - 50359-04
Chrome Footpeg Extensions - 50924-03A
Braided S.S. Fuel Line - 63020-04
Chrome Keycaps - 71802-03
Turn Signal Module - 91698-02
1/4 Covers for Engine Bolts - 94830-02
Chrome Fuel Tank Hardware - 62920-00A
Chrome Windshield Molding - 59213-96
Head bolt Covers - 34901-94C
Head bolt Cover - 43857-00
Jiffy Stand Kit - 50309-02
Chrome Lower Belt Guard - 60491-02A