Well lets see my first motor was torn down 5 times and finally i paid on my own to try and fix it. Thus far this new 09 I love the ride, handling and can not get rid of the vibrations in the bike and it is now infront of the Area rep. My 103's have run Fantastic, My 124 has run fantastic, only motor I have had issues with is the 110. I ride nearly every weekend with at least 3 other 110 SE Riders 07, 07, 08, 09 (mine) Everyone but myself has had the engine replaced, hence my advice to you. Definitely 103, 113, but i would not bore the cases and do a 110 if I bored the cases it would be a 113,117, 124 motor. The 04' 103 runs fantastic it makes 117/115 and starts every time we take it out with 56k miles on it. The 05' 103" i totaled had 30 something K on it and ran fabulously. My current 05 with 16k no issues.
That is why I am making the suggestions I am too you.