Personally, the 3 cylinder 120 HP engine makes so much power and weights so little, there is no reason at all to use the larger 4 cylinder engines. My engine weights the same as the Rotax 912 100 HP engine used in the Xenon, yet has more power than their turbocharged optional engines. And I am burning less gas.
I absolutely would have gone with the triple Ron, but they are hard to find and when you do find one they are expensive. You guys got lucky, it will be a few years before the next generation triples are plentiful and cheap on the used sled market. THe 4-cyl, on the other hand are plentiful and it is very easy to grab one for $3500 or less. 3 sold on Ebay this week alone, the one I got for $3100, another went for $3250, and the 3rd sold for $3550.
The cheapest 3-cyl (RS and FX series) on Ebay? Ha, they didn't even meet their reserve, and guys were bidding $4000 and up.
I've been watching and bidding on and off since November. This is the best deal I've seen that I had a chance to grab. I am driving up to PA to pick it up, so throw in another $300 for the trip. I am still under $3500 all-in. If I buy a sled in the Rockies, or way up in New England, it will cost about $600 to ship, so I figure I saved a few bucks there as well.
There is a dealer that will sell an FX I found, for about $3500. But he is charging $190 for "paperwork", PLUS sales tax, so there goes another $600, plus I'd still have to spend $300 to pick it up. Now I would be out $4600.
Got to take what you can get sometimes. I was getting to the point where I really needed a project to perk me back up and put the twinkle back in me eye. Looking at a blown motor sitting in a gyro sitting in a hangar that costs $100 / mo....since August....well, that don't add up neither. Time to git'er done!