Daltonlanny,
you're welcome.
I have modd'ed 1 of the Para. 2000's, two of the 1100's a handful of Zpres, and numerous other manufacturer's pre and power amps.
With the exception of the vishay resistors (available directly from Vishay, but fairly large minimum order quantity), all the parts you'll need may be procured from Digikey.com or Mouser.com parts catalog. The toriodal power transformers are available from several sources on line, such as Plitron, Antek, Talema, and others.
As poster 2002 mentioned, the parasound circuits are done well. Once parts upgrades are done, these units really sing.
I used to think if one would spend enough money one could buy a pre amp or power with these parts already installed. Unfortunately, that is not the case; even with 5 and 6 figure priced gear.
A nice amp is the Parasound HCA-1000A. In its stock form it can be a bit bright, especially with the likes of Paradigm, Thiel, or Infinity spkrs. After the 1000A has been gone through, only then can one hear what this amp really offers for a reasonable price.
Taking the never ending upgrade train to sonic euphoria will never get you there, only with the truly good parts, does one begin to approach what all audiophiles are after.
As mentioned in the earlier post, if the para pre in your system does sound a bit lean or thin, it can be quickly corrected with a change of the bypass caps to a film and foil cap rather than the metalized film types that are so commonly used.
Best of luck in working through your pre.