I had one of the first Ultimate 40s and flew if for an entire season before selling it. Mine had a YS63 in it and it was a perfect engine/airframe combination. I used all of the standard DP hardware on mine and also had some concerns with vibration before the first few flights. I sealed my control surfaces, replaced some of the linkages with tighter connections and tightened my pull-pull connections ever so slightly. There still was a bit of vibration, but it didn't hurt a thing in flight. That little plane was rock solid and a real performer with the YS63/APC 13x6 combo. I too suffered a sheared off wing attach fitting on the upper wing center, but I had replacement parts within 3 days from DPM and never had a problem after that. Even the tail control surfaces on my big DP Ultimate and DP Edge have a bit of vibration during runup, but once you get in the air, it is not an issue. I say fly the thing w/ the Saito and you might be in for a pleasant surprise. Mine weighed in at 5 lbs even with an empty tank and you'll never find the kind of stability and control authority in any other plane of this size. It flies as good as my CG Ultimates did, but the light weight just made it a little trickier in wind. Good Luck.