I've been flying my NP 260- the blue one - since last summer. OS 46 and she really does a good job. The thing is so light I would hate to think of anything larger under the cowl. Well, maybe the OS 55....

I did have trouble with my muffler always coming loose. (Slimline pitts) and found out that it wasn't tightening up due to it hitting on the motor mount. When it melted a little channel in the mount, it tightened up nicely. It's an awesome plane and keeping the motor compartment light it walks in for landings. It's one of those planes that I like to fly when it is "too windy."