Sonus Faber Venere 2.5 amplifier Recommendation

I have a pair of Sonus Fabers Venere 2.5 and found similiar issues controlling bass roll off. I have them a thick carpet laying on a concrete slab foundation. I corrected issues by going to my local granite stone company and had them cut and polish  2-16"x16"x1.5" 20 lbs dead weight per platform plinths and placed the speakers with the spikes protectors on platform with equip spikes and found not only tightening the foundation bass but had a great improvement overall on the mid range too!
I also bi-amp with a Krell KSA 250 on low and Audio Research VT 130 se on the high and all I can say was wow now these Venere's are really performing with a huge sound stage  and very black deep sound. Overall like a total different performance!

Enjoy music!

Yes 250 watts pure solid state Class A on Lows and 130 Watts tube power on highs. Best I've heard to date on my system. I also have a Prina Luna Dialogue Premium pre-amp driving a analog active balance crossover making a perfect bi-amp setup! 
As far as the spikes I saw no good reason nor justification to the replace the stock spikes. Yes even though the granite stone plinths are dead heavy movement for tweeting the speaker placement helps tremendously!

Enjoy music!