Missing tube integrated for Klipsch Forte III?

I think that the triode (6550, KT88s, etc) amps are going to be better top to bottom if you want a more linear/accurate tube presentation. If want a warmer and thicker presentation then the pentode (EL34 EL84) amps will be better.

I far prefer the triode amps but I like a more neutral presentation and would tend to alter the presentation with tubes or cables as needed. I think it is easier to make a neutral amp warm than to make a warm amp neutral. 

The Fortes never struck me as a very subtle speaker so some of the more sublime and nuanced amps might find these qualities lost on the Klipsch. I think that there is a good synergy between Klipsch and tubes. I cant stand S.S. on Klipsch speakers, but have not heard them driven by really high end S.S.

I believe that the Fortes have a rear firing woofer. If this is the case, I cant imagine putting them close to a wall would be a good idea.

They don't have a rear firing woofer. It's a passive radiator.

I own the Klipsch Forte III's along with several other speakers and class A solid-state amps and tube amps. I totally agree with those that say you should add one or two powered subwoofers.
The bass is good without the subwoofers but I don't think you will hear what you desire without subwoofers.

You need to adjust your expectations or add some subwooferage.

O.K. so its a passive radiator. Do you think that putting a speaker with a passive radiator against a wall is a good idea?