Not all Sundowners are aerobatic - easy to spot though, they have strakes on the side of the cowl and an extension to the vertical fin below the tail.
A Sundowner is a capable tourer with the ability to do loop, rolls etc. for fun but would not do well in even a beginner competition I think.
I was looking at buying one six years ago - in the end I went with an Archer II and no aeros - mainly due to availability of parts.