6 Ohm Capable Yamaha Receiver (HTR6260B)

[Diggger]

I don't know too much about receivers / speakers, I just bought a new receiver and new speakers. I was reading about the capable ohms and was wondering if my set-up would be fine.
My receiver has an output of 6 ohm's and my rear speakers also have an output of 6 ohm's but my towers and center has an output of 8 ohm's.
I have read that the receiver and speakers all should have the same output ohm rating but as described, mine does not.
The system sounds great but I am wondering if not having the same ohm rating will damage my receiver / speakers over time?
Thanks