Welcome aboard, and a nice looking ride you have there.
I would not hesitate to go to 103", it's proven to be much more reliable that the new 110" (unfortunately).
Aside from the conversion kit, I'd certainly consider the following to make it even better and more reliable:
. Oil cooler (if you're not running one now)
. Gear Driven cams (get rid of those MOCO tensioners!)
. Adjustable Push Rods
. Feuling oil pump & Feuling or Delkron cam plate (or even the new MOCO SE version)
. SE 103 heads (skip the porting and polishing unless you plan on racing it)
. Maybe a new exhaust system of your choice (true duals or 2 -1)
. Defininitely a Screamin Eagle Race Tuner or Power Commander set up W/Dyno
Sit back, hold on and enjoy the ride!!
Joe