Big Sky Audio to upgrade Adcom GFA-535ii?

I am wondering if any one has experience having Big Sky Audio ( upgrade their Adcom amps. The following is the recommended upgrades for $299:

"Install high quality audio grade capacitors and low noise metal film resistors in working driver, output stage, and power supply circuits for greater musical clarity. Areas targeted for improvement include the input circuitry, feedback loop, output stage biasing, output stage & power supply bypassing. The 535II uses flat pack style power supply rectifiers instead of the larger bridge type rectifiers so we are prevented from using soft recovery rectifiers for reduced switching noise but instead add bypass capacitors which will do the perform the same noise reduction."

Is this worth it? I have the following: Adcom GFA-535ii, Adcom GCD-700, Adcom GFP-715 driving a set of Krix Lyrix speakers. Looking to add a turntable and Peachtree Dac*it in the near future. I am looking to keep this system for another five years (I purchased the GFA-535ii in 1994) before upgrading (wish list is Pass Labs X150.5 or Bryston 3B). Thanks.

I would not do the upgrade. For less money, you can buy an Adcom GFA 5400, which is much newer & better sounding than the 535II.
Another factor is resale value. The day after your 535II comes back with the $299.00 mod, it will sell for less than just the upgrade price, on this site.
I've owned the GFA5400 & (2) GFA 5500s. They all sounded better than any of my (4) Adcom 555IIs...
I wouldn't spend the money on the little Adcom either. About roughly twenty years ago, I came across one already done. I can't remember if I bought it, or if it was part of a trade back then. Another thing, that amp is 60 wpc @8 ohms, I believe. The one I tried was the 545 or 555 series. It may have been done by a well known (for Adcom owners) called Musical Concepts, if memory is correct.

The sound was better that stock, but it sure didn't compete with some of the better stock units back then. Also, the resell value was close to a stock one. The main power supply capacitors don't last as long on some amps like they used to. Those main caps are unpredictable anymore nowadays, though. Some amps had bad production batches go bad fairly quick. If those go, then you'll have to put more money in it, or sell it as is, at a loss. I don't believe those will be replaced by them. Plus all the other older parts will still be there. Even with this aside, I still wouldn't put $299 in it.

I think upgrading to something newer makes more sense. I'm not familiar with the newer ones for any recommendations. But, something under 10-15 years old may get you more for your money, may sound as good as the upgraded one (possibly better?), and may last longer.

I'm not familiar with your speakers, but make sure another amp can drive 4 ohm speakers like the Adcom can. I looked on the net at your speakers, and they do need an amp capable of running 4 ohms speakers all day long. Maybe go with a little more power than the 535II too. One person wrote a small review, and said your speakers are a little bright. If they're correct, make sure a newer amp isn't bright too. That would be a bad combination in my opinion. Try to find some reviews, and shop around for something newer, is what I would do.
This is a case of trying to make a sow's ear into a silk purse.
I agree what's said above, don't do it. I know a guy who had his Forte 4A (amp) professionally upgraded. When he got it back and broke it in he thought it didn't sound as good as it did before it was upgraded. So you take your chances.
Wow! Another Krix owner! I'm throughly enjoying my Apex 3.1 w/my slightly modified 50w Rotel 951. (The Apex's are 8 ohm spks.) I also own the larger version of the Lyrix, the Symphonic's. They are an easy 4ohm load and 90dB effecient. i have to agree w/the other posts, i'd personally not spend the $ to upgrade the 535. Once owned the Bryston 3b, very powerful but grainy. The Bryston 4b ST was worlds better. Perhaps the recommendation for the Adcom 5400 is the ticket if you want to stay w/Adcom. Cheers!
I had an adcom 545 (1st gen) and was contemplating the same upgrade you are talking about, only with the next step up ($500 or $600 md whick included black gate caps, or something like that, can't really remember now). From the reviews I've read, the 535 is supposed to be the most "musical" (best sounding?) out of all those adcoms of that era (545, 5400 etc). Honestly, what I'd do is leave yours stock, hang on to it for a second system for the bedroom or something and put the $299 towards a different amp. You could probably only get around $100-$150 for your adcom, just keep it. You might need to save up more than $299 for a step up in terms of sound quality. More like $500-$900. Adcoms to me are a bit bright and in addition lack bass but they aren't horrible by any means. I sold my 545 for $100 and spent $800 on a classe ca-150. I would look into some conrad johnson amps or oddessy amps if I were you! Good luck!
I've had 535s both I and II (a couple of each actually) and I like the 5300 better...used as a secondary amp now for outdoor speakers (or backup if my main tube amp goes down). The good news is nobody agrees with me, so a nice 5300 can be found for very little money, especially compared to the well regarded 5400 and 5500...I think its bass is warmer and it has an overall more refined sound than either 535. But like I said...I'm the only person who feels this way...I'm all alone...*sigh*...
As above,

step up to the Adcom 5400 or 5500.
See? I rest my case.
Thanks for all the input. Most likely just going to be happy with what I have for now.
Nagaworks, that is a stellar idea! One I also need to come to grips with :-)