Naturally, any part swapping (outside of tubes) will void your warranty. Over the years, I have seen a few pieces of our equipment with user "modifications" returned for repair. In some cases we were able fix the unit by removing the modifications, other times not.
We have tried the exotic/magic parts in our units several times, and the times I got to listen to the "upgrade", I didn’t notice an improvement in the sound. At best, the unit sounded the same; however, most of the time the sound was worse.
One other thing: We do NOT recommend tube rolling in our hybrid power amps because the circuit is balanced for the tubes installed.
Thanks,
Larry