They all basically have the same wing and are quite aerobatic. Here's a quick breakdown of the Extra lineage:

Extra 230: Single seat, mid-wing, based on the Laser 200.
Extra 260: Single seat, mid-wing, outgrowth of the 230. More HP.
Extra 300: Two-place version of the 260 with a mid-wing, 300HP.
Extra 300S: Single seat, low wing, 300HP.
Extra 300L: Two-place outgrowth of the 300S, with an even lower wing.
Extra 330 aka 300SX, 300LX, 330S, 330L: A version of the 300S or 300L, respectively, where the tail is modified with larger surfaces and counterbalances. Nice for models, because the rudder is a bit bigger. These planes can also have up to 330HP.
Extra 200: A version of the Extra 300L, with a 200HP engine installed. The nose is a little shorter to reflect a four cylinder engine.