What will this be used for? Bashing or racing? I have found the CC Neu 2650 makes a perfect all around bashing motor on 4s. On 5s, it can do speed runs all day long in a wide open space. For racing you probably want what has already been mentioned - something around 2000 kv. The Neu 1512 2.5D is also a good choice.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy