How competitive is the S4 for autocrossing?

I have taken my wife's Mazda3 automatic to the local autox's and have won 2 novice classes (H stock). Is the S4 towards the bottom of the group for it's class (D-stock)?

It's not, when it's stock. They run in D-stock, which is slow, they understeer like a bitch, and they can't stop quick enough.