Hard to pick one, there are so many now. But the likley order for the main mods:
1: Lower and set back MX wide pegs with extended shifter (I'm tall)
2: Updated suspension - Ricor front and rear w/heavy rear spring (I'm big and carry lotsa gear when camp/touring)
3: Raised handlebars (see 1)
4: Modified fairing w/adjustable wind screen (up for quiet highway, down for back road agressive rides)
5: Mikuni VM38 carb (simplicity, access, throttle response, low rpm smooth)
Others: Big rear rack, license plate relocate, HT side racks/soft panniers, skid plate (mandatory), heated grips, accessory power for GPS/cell phone charge, single LED voltmeter.
Always a work in progress.