Maybe is a tough question, sorry but it is a hard decission to make either. I happily have a pair of Watt & Puppy 8 with Electrocompaniet mono amps "nemo" and a Tag Mc laren 192 audio video as preamp. I am sure I want to buy an audio research reference 3 as my new preamp but I have serious doubts about the amps. This is between new krell 600 evo and Boulder 1050 amps. The price is similar, more expensive boulder amps but I want the best of them. I know it would be really dificult to find anyone that have listen to both but I have to try. Thank u all just fot reading my post, I appreciate it.
The Krell Evo gear is designed to have optimum performance with other Krell Evo gear using the CAST system; I don't think you will necessarily be getting all you paid for with your mix and match approach. Make sure you audition the amps hooked up to a CAST system and a conventional system to get an idea of the potential performance differences. I've heard the 600 with other Krell Evo stuff and was impressed with its ease and dynamics and low noise floor.
See Wes Phillips' review of the 202 & 600:
BTW - the amps are extremely heavy & cumbersome (weight is not evenly distributed and there are no handles), and not something you'll want to move around much.