I used a 4*60 in the Basic class last year. I have an OS 91FX with a Bisson Pitts muffler in it. I also have the CG set a bit aggressively (in other words, back farther than recommended, although I don't remember the measurement off the top of my head...)

I've never had any problem stalling or spinning the plane.

This plane cannot be used for any class except for Basic. The 4* is *not* a scale plane and is therefore not legal in any of the higher classes.

This doesn't mean that you can't fly the maneuvers in the other classes, you just can't compete in them. I have flown several of the Sportsman sequences (including unknowns). I can fly most of the Intermediate maneuvers as well. I don't have enough power or the symetrical handling to fly the sequences well, but it's still a lot of fun!

Dave.