first off one piece bars aren't compatable with the a model because it has a smaller head tube therefore the fork tube is to small for one piece bars. but you could make your own. and wider bars do help whip faster if you are comfortable with them
Getting a pro model will help you whip way better than getting bars for your new A. Mostly cause new A's will hold up to about two whips before they break.
i can double flat on 14. im riding 18.5 now. just ordered 16.5 wide. i like all bar widths