Tekton or Klipsch

Magico,
As Al noted, your Rega Brio amp provides 40 db of gain which is very high re)active to many other amplifers. I’d bet that your Tube Cube amplifier gain output is likely in the range of roughly 25 db. This would be a much more suitable/flexible match for the higher sensitivity speakers you are interested in. Excessive gain offers no meaningful benefit.
Charles

Magico,
There are Double Impact owners with rooms of similar size who've reported successful outcomes. Perhaps some modest room treatment could prove to be effective. Al raised a pertinent point regarding system gain and using higher sensitivity speakers. You do want to avoid a scenario where use of the volume control is limited to a narrow range i.e.you can't go above 9 or 10 o'clock because volume would be too loud.

Both speaker brands will work very well with a good quality tube amplifier,  I believe you'll be quite happy with this direction. 
Charles 

Hello medigo,
You are quite impressed with the sound of the Klipsch Heresy so I suspect you will very likely enjoy the Forte as as much and possibly more so. I am curious as to your upcoming Forte listening session, keep us posted.

I’ve heard the Tekton Double Impact and also the SE version of this model. Based on my listening I feel confident in saying that they are very capable of playing many genres of music well. In my opinion these speakers are revealing of associated audio components. They easily reflect changes in amplifiers (and preamplifiers/DACs) in the signal chain. The better the components, the better the sound quality.

This is a good result as it demonstrates the speaker lacks a dominate sonic signature that masks the contribution of the driving amplification. These speakers definitely allow distinctions between amps/components to be recognized.  They are in my opinion very good quality speakers. I believe that you'll be happy with either brand of speakers. What amplifier are you planning to use? 
Charles