I fly mine both with and without SFGs. I like it both ways. I think the SFGs are mostly for 3D. It makes it KE better (altough it KE great without them, just slower higher alpha with). I can hover easier with them and it will do quite a bit better flat spin with them (pinwheel type for the purests) I flys prettier without them. More scale like and faster. It's easier to land without them and it does fly better in the wind without them.

Mostly I fly without them. I have planes that do better flat spin anyways so I'm about 75% without and 75% with.

Thanks
Barry