The ones lots of people have suggested include (but not limited to):
1.) Rudder and Elevator pushrods are too skinny. Instructions say you should slip some plastic tubes (included with the plane) over them where they come out of the fuselage near the tail, that sounds sort of mickeymouse. A number of people have replaced them with thicker wires, around .045" or thicker. Others have grafted 2-56 or 4-40 threaded rods onto the originals where they come out of the fuse near the tail, around 5" long, and put Kwik-links on them to attach to controls.
2.) The ESC that comes with the plane is marginal at best. It apparently has a linear BEC that heats up easily, and may not be able to handle the six servos the plane has. Some people report strange motor cutouts, even when they are not flying at high power settings, might be due to this. Not a bad idea to replace it with an ESC that has a switching-mode BEC, those run a lot cooler and are more efficient. Or possibly a completely separate BEC.
3.) Some of the propellers that came with the SSS, have been found to be mis-formed. Instead of the blades being 180 degrees apart, some have been more like 178 degrees or so. Very odd, and they won't ever stop vibrating. An APC 8x6E is one example of a good replacement.
4.) The original battery is a 3s LiPo, which gives OK but not spectacular performance. Some have replaced it with a 4s battery, which performs noticeably better with the original stock motor. If you do this, it's even more important to replace the ESC too.
5.) The main spar brace is a fiberglass rod that is very strong, but weighs a ton. Some folks have replaced it with carbon-fiber tubes that are like 1/4 as heavy but still very strong.
6.) A few people have reported that, in a steep dive, the SSS's ailerons no longer respond; though elevator is fine. After you pull out and slow down, everything works fine. It's not clear why yet - maybe the aileron servos aren't powerful enough, or maybe the wings twist slightly under heavier air loads, or maybe other causes.
7.) Some folks have put in more powerful motors, and gotten great performance as a result. This usually requires a higher-amperage ESC, and possibly a different battery. Some of these motors bolt right in and are a direct replacement with little effort needed. Others are larger diameter and need the plane's motor pod hollowed out, and sometimes the motor mount modified. Keep in mind that the SSS is a powered glider, not a racer or a stunt plane. Fast, steep climbs can be fun, and even useful at times. But if you want super aerobatics or high speeds, you're probably flying the wrong plane.
Bolt-in, 655W, steep climbs: http://www.hobbyking.com/hobbyking/s...dProduct=18226
Needs engine mount mods, 1000W, vertical climbs: http://www.headsuprc.com/servlet/the...ushless/Detail
Lots of other motors, from many sources, are good too.
8.) Cameras, gyros for stability (especially with a camera), two-wheeled landing gear, LED lights and strobes, you name it, it's probably been tried. And if it hasn't, what are you waiting for. The sky's the limit.
9.) When you modify your plane, check the Center of Gravity (G.G., or balance point). The instructions specify a location 100mm behind the leading edge of the wing. Most people seem to get good results if it's from 90-odd mm to 100 mm. I've flown mine with anywhere from 93mm - 100mm with good results.
I've also flown it with C.G. more than 100mm behind the leading edge, but the plane was tricky to handle and stalled a lot, which I consider unacceptable. Your results may vary, of course. But the SSS seems to be VERY sensitive to C.G. location.
Anybody have other mods to suggest? Lots of things are possible with this plane.