Integrated for bi-amping with AtmaSphere MA1s

My speakers (Ascendo ZF3s) have separate terminales for each driver.  I am currently using Atmasphere MA1s for the mids and tweets, and using a Pass X1 and Aleph3 for the woofers.  I'm also using a set of old Entec LF20 subwoofers crossed over with a Behringer Ultracurve pro for the really low frequencies.  I would like to replace the X1 and Aleph3 with a more powerful integrated, and am not sure what to use.  I've been away from this hobby for a number of years, but my first instinct when I think low frequencies is Krell.  The S300i looks intriguing, but I've read that it comes from a dark time in Krell's history, and may not be terribly reliable, and not up to the stnadards of low-frequency reproduction Krell is known for. 
Is this a good choice?  What else should I consider?