If you are going to be racing, the 9XL is going to be the way to go. Depending on how tight your track is, you might even be better served by the 10XL.

Don't get fooled by the high kv ratings of some motors. With the Feigaos especially, you'll want a large can (XL) motor with a relatively low kv rating on 4S lipo and take advantage of all of the torque and gear up to attain speed.

I have a thread in the brushless section entitled something like 8ight T 9XL or something like that. I have a link to a video in there that will give you an idea of the kind of performance that you can expect.