Rotel RA1070 vs Krell300il/Krell 400ui Intgr amps

Going to a Krell from Rotel isnt going to give you a more "agressive" presentation. That Rotel unit is better than its pricetag suggests. Like Sonus Faber, Vienna Acoustic speakers are going to give a very mellow laid back style of sound.

I'm not sure Krell is the best answer. Their integraded amps, especially, the 300i series is a little mellow to begin with, a little rolled-off up top. It has a nice sence of flow and presents music as a piece, but if you are looking for agressive it is not your answer. Try Bryston.

To followup on what Kchahoc said, Bryston is a good choice. Currently, they only offer the B60 integrated, which may be underpowered for some systems. I read somewhere that they are working on an integrated based on the 3B-SST. You may want to inqiry about that.

The real truth of the matter is that the speakers probably shouldnt have been bought in the first place if they arent coming across as the owner would like. The speakers are what make the real difference. Amplification(even tube amps)and source units should be done for minute fine tuning at best. Bryston isnt exactly agressive either. Ive actually heard a pair of Bryston &B's on more than one pair of Vienna Accoustic speakers. The sound is still very much laid back.