To add to the above posts:
I think it's possible to aerobat any aircraft that has a "U" category certification, since the majority of aerobatics maneuvers, up to standard level, can be done between -1 and +4G, with speeds well below Va.
HOWEVER
Sooner or later you will botch a maneuver and you will need to exceed "U" category limitations (either G-load, or speed), to recover. And then you'll find yourself with no safety margin whatsoever ("U" category limits, from memory, is 4.4G) and no G-meter to find out how close to the limit you actually are.
The most insidious of these is actually the barrel roll. A proper one can be executed with less than 2G and no height loss but if you don't balance roll and pitch against each other properly, you may find yourself inverted, nose down and building speed fast. In that situation it's very easy to exceed both speed and G limits simultaneously. Not to mention the 1000 feet or so you may need to recover.
So once again: Only perform aeros in an aircraft that's cleared for aeros, and fly the maneuvers according to the POH (particularly entry speeds). If you have no experience, get proper instruction.