I have no idea about the RIO's inlet's and outlet's, but all you need to know is they are very unreliable (they tend to quit without notice) and are submersible (which means you will need to mount the pump in the resevoir, which will heat the water).
Spend a little extra and get at least a Mag-Drive 250 or 350. I saw a post with a new discount coupon for $10.00 of a purchase of $30.00 or more (making these almost as cheap as the RIO) at
www.PetSmart.Com.
Trust me, don't go cheap (I saved a little money buying cheap hose, then bought good hose later, and a new processor

)