Replying to Racing in freestyle boots.

Now I know there is no such thing as a park boot and yada yada yada but I was wondering if anyone had tried driving a GS or Slalom ski with an Ace of Spades boot or an SPK pro or one of the Full Tilt stable that isnt super stiff?

Reason I ask is that I have been asked to join a race squad for a months training and competition and I need to work out whether to spend the ££££ on stiffer boots or not.

My gut feeling says try it and see as the AoS isnt that flexible and I haven't raced in years. However the upright canting might be too backseat to drive a stiff ski.