Upgrading Odyssey audio Khartago

I'm getting the upgrade itch, and my beloved Khartago is probably the next to go. I'm considering the following replacements:

1. Parasound A21
2. McCormack DNA-?
3. Odyssey Stratos (not sure if this is much of an upgrade over what I already have)
4. Pass labs X150.5 (this is my dream amp, but I most likely won't be able to find a used one that is in my price range. I like to think that the 3 amps above at least come close in performance to the Pass.)

Also I'm driving odyssey lorelei speakers with them and primarily listen to rock.

Which would you go for, or do you have any others in the sub $2K range, used or new?
I have a Stratos extreme+++ driving a pair of Kismet Reference speakers. The Kismets are very much like the Lorelei speakers, but with a much improved and more expensive crossover. The sound is to die for. I have zero desire to change. It blows away the Parasound amp as I had one previous
I the extreme+++ cyclops, is there really a significant difference from the cylops/khartago vs the stratos. Maybe I should give Klaus a call
Why not talk to Odyssey and ask about having the Khartago
upgraded? If yours wasn't hot-rodded when originally built;
I know they can double the capacitance in the power supply,
and offer 52 driver board mods as well. Have you considered
going dual mono and taking advantage of their conversion(of
your existing amp) offer?
The dual mono approach is definitely something to consider. It would be the same amp, but the separation of channels and increased space for better power supplies is intriguing.