Mods for a PS Audio HCA-2?

Fiddler, I saw some mod packages listed here starting at $600, and adding $60, or even another $120, for a possible $820 total. It's not that this amount is out of the question, but I've been toying with the idea of bi-amping, so double that amount and add another HCA-2, and it's getting a little steep for me! You mentioned $75!!! Did you do the mods yourself?
I also have power hungry 4 ohm speakers, but the amp drives them pretty well so far. The reason for possibly bi-amping, is to try to improve the mid-range of my system with some different drivers and an active crossover
If you or Sean can let me know who does the work, and how much, then we can go from there.
Calanctus, You did the work yourself?

F1a, In response to your above question about piano, I recently purchased a Consonance 2.2 CD player, and plugged it direct to the HCA-2. IMHO piano sounds really good. So your decision to change your source, is probably a good one.
Also, if you are going to mod your amp, let me know where and how much. I don't think I'm going to try doing it myself. Sonny

Wehamilton, What you had done, sounds alot like the mod package that's being advertised here on Audiogon. What was the entire cost, if you don't mind. I'm across the country, in Ct. I'd like to find someone closer.
Also, I thought that Fiddler said that the additional mods didn't result in that much difference in sound?
Sonny