Mine had the std. wing mounted gear, which, despite much abuse, I never did break the gear mounts. Bent gear, yes (many times). Broke, no. Mine started out with a Quadra 42 on it, and ran a 20" prop. The weight was not an issue, nor was prop clearance. If you go back far enough, one gentleman mounted a 50 on his....
I don't think the 40 twin will be an issue. Should be a smooth power house the plane will handle with ease. That said, though the Sportster has proven itself a great sunday flier, I think there are much better flying sport planes if one is looking for the performance a 40 twin is capable of.