If I remember correctly Randy did exchange components on his MPS-1 a number of times before giving up. A year or two later when I spoke with Lonnie he wouldn't even bother with replacing or exchanging anything, he simply suggested that the XPA-2 and the M80s were a mismatch and offered the suggestion of two XPA-1s to drive the M80s (at twice the price).

"If you try to turn toward it, you go against it."