Hi Mes, I am an ARC enthusiast so I think the Ref 2 MkII will work perfectly, but ultimately you should take some cd's to your ARC dealer and give the Ref 2 Mk II a listen for yourself, some like ARC and some don't, but most people who know will tell you that their preamps and power amps work synergistically together. But for your system, the direction the 300's took you in that you like will be enhanced in the same way but with evem more magnitude when you do the preamp. Have fun and trust your own ears more than all our opinions, your system synergy and room iteractions are important factors that we dont have information on yet, as well as the fact that we all hear into the music differently and have different priorities in the presentation we want from our system. Let us know how your listening goes. Have fun.