I have:
Mains-RF-3's
Center-RC-3
Rear-Rf-3's
It was my intention to match all my speaker the best I can. Maybe later also third pair of RF-3's for front and rear center channel.
But in your situation I would go for the RS-3's.
Why?
Well, look at the specs of your RP-3's and those RS-3's.
Both 95db and 110w power handling,the enclosure is sealed for both.
Also the woofers are both 6.5".
Not that they would sound very similar, I don't now. I think that the RF'3 would be
overkill as rear with 98 db and 225w.
But than again you have to place them
RS-3's bookshelf or wall mounted
RF-3's floorstanding
If that's no problem go for the RS-3's.
Sparky