The sidearm shot generates more power and snap than a backhand throw. (generally)
Most players have to throw a disc that is overstable to counter some of that spin and power.
Two of the most popular discs for this shot in my area are the Champion FireBird and the Z flick.
Joe G absolutely swears by the Star TeeRex for his sidearm shot and it works perfectly for him.
No matter how much power and snap he puts on it, it is guaranteed to come back to the right because it is so overstable.
Other popular overstable drivers are Max, Monster, Banshee, Viper, Whippet and the XCaliber.
Depends on the shot usually. For early turn I like the Firebird, less distance and forsure stability. for longer distance I step up with a Force, Teerex, or a destroyer. But for maximum crushing distance the Groove is one bad boy you can put a long way.