Back to your original question - you want to do more than fly around in circles. I ran into the same problem - the airplanes are too stable with all that gear under them, and a lot of extra weight so they can land on water. I found a kit called a "Beast" in R/C Report several years ago and it is very aerobatic. It's basically a flying wing with a pontoon down the middle under it and floats under each wing tip. If you set it up properly it will spin, snap roll, or anything else you want. It's a .60 size plane, which will fly with a .40, but not as well.

Let me know if your interested in it and I'll see what I have for info.

Bill