how does upgrading work with Krell amplifiers

HI I was just wondering if any one has experienced upgrading a Krell FPB-600c
I need to know how this works with Krell and how much it cost.
I have just purchased a unit with only one year left on its guarantee.
If I upgrade does that stay the same?
Warranty will certainly be void after any upgrades or mods inside the box.
If you don't like the amp how it sounds originally, you'd better change it. I'm sure there are many who would rather take the original product with warranty especially if such is transferable. You may exersise mods on products with no warranty.
Why don't you contact Krell and ask them. Here is a link:


You may exercise mods on products with no warranty.
I thank you for your advices. I posted on the weekend I will call Krell today and find out what’s up with the amplifier. It was just made in 2000 maybe I have more time on the warrantee.
I will do the upgrade not because I don’t like the sound but to keep it up to date. I hate falling behind to the point where it is not upgradeable.
Is the upgrade a valuable one?...i.e. just what does it improve?