Your Revel F35s are reported to have a sensitivity of 90 dB.
The Denon AVR-X2700H with a rated power output of over 120 watts per channel for a 6 ohm load. However, those Revel speakers have an impedance going down to 3.5 ohms at around 185 Hz. Depending on the volume at which you play your music, it's quite possible that your receiver is struggling to drive them. If so, you would need to replace the X2700 receiver with one that has pre-outs for driving external amplifiers.
As for external amplification, I would strongly recommend the Monolith 3 channel power amp, or one of the newer generation Class D products, either Buckeye or VTV amps..
This is a review and detailed measurements of the Revel F35 floor-standing speaker. I purchased this through my company because there are external anechoic measurements available so we can compare. The F35 costs US $1,600 for a pair (sold each at US $800 in case you want a center speaker). It...
www.audiosciencereview.com
Here is a link to help you determine how much amp power you need to drive the Revels at your desired SPL: