RE: seagull extra 300s
I had one of these until I tried to do a snap roll too low, went to deep into the snap and smashed it in.
It was an ok flyer (I had an OS 61 2stroke on it) but I needed more power. The advertised weight of 6-7 pounds is wrong. Mine came in at 8.2 pounds and would tip stall in a heart beat if I pulled too hard on the elevator in a turn or loop.
It is a good looking plane, but not for those without lots of experience in twitchy aerobats (like me). Also, it's control surfaces aren't large enough for 3D flying (which I'm not into) even if you overpower it by a large amount.
Good luck.