Sonus Faber Olympica II or III?

I'm planning on purchasing new speakers soon and am very interested in the Olympica series. I have recently learned how important it is to match the size of the speaker to the size of the room, but I'm not sure about which of these two speakers would work best in my room.

It's a 20ft x 17ft x 8ft space. My electronics include the Odyessey Tempest Extreme & Khartago Extreme. For music I primarily listen to rock and jazz along with a little classical, electronic & blues mixed in.

My preference would be to get the II to save on cost, but I don't want to get something too small for the space either. I have heard both sets of speakers, and enjoyed both, but they were in smaller rooms than I will be using. Anyone have any experience with the Olympica II in a room similar in size to mine?

Thanks for any help.
I think the II would be fine. I was impressed with the I's, and if you really want the final amount of bass, then adding a REL or similar quality sub would likely be less expensive than the IIIs--although I don't think you'll find you need it.
Hi :

Most high end dealers will let you borrow or audition gear if you ask. Ask your local dealer if you can audition a pair for the weekend and see what he has to say.

Norm L
I replaced Wilson Duette's with a pair of Sonus faber Olympia I's... in a room that's 24' by 17' with a 22' high ceiling. The Olympia I's fill the room just fine.
That size of roo - Olympia I; OR, if you can find a NOS I would suggest the Cremona Auditor Ms. Add a REL for the lower most notes and be happy. Probably can find them for $3000/pr with stands.
Thank you for the responses. I've got a pair of Kef LS50s in my second system, so I want to get something larger for my main one to have variety. But, it sounds like the Olympica IIs should work great in my listening space. I really appreciate your input.