OEM props are available from Amazon. I use props from masterairscrew.com myself, but I'll warn you that a lot of folks feel OEM is the ONLY choice. I'd avoid carbon fiber, from some of the horror stories I've been told, but the MAS screws seem to work just fine on both my P3S birds. As to the motor issue, I have no knowledge in that area. Mine are stock. If your motors have the same threads as stock, there shouldn't be an issue. Just make sure they're snugged up before take off.
Choices are many. Use your own judgement.
Brad