kudos

Hi Guys, i just got a kyosho inferno kanai MKII and was wondering what the best motor to get would be. I don't care about anything but power, Whats O.S. motor would you recommend, is the RZ .21 good? The reason i'm asking about O.S. is because i can get a hold of O.S. engines alot easier where i'm from. If O.S. engines will not make the power i'm looking for then please recommend a good engine for me.

Thanks.