companies that modify equipment...opinions

I have no interest in mods, or modded equipment. It is a fashion statement as much as anything else.
I view it as 'the grass is always greener' effect.
Folks who think they can have an edge. It is like a 'cult'.

Now really some mods work, some are just a waste of time.
I would just go buy a better stock item.
The OP asked for opinions. I am giving mine.

I remember the guy who went for the mod too far. Complaining they ruined his Counerpoint preamp with too many mods.. Apparently changing it into crap.. in his opinion anyway.
So not only did he lose his wonderful preamp, he paid through the nose for doing so too.
This is the sort of foolishness involved in 'modding'
Total crapshoot IMO.

Like I wrote, I would NEVER pay someone to mess around with any electronics I paid a lot for. Period.

As Elizabeth stated, I too have no interest in modifications to original designs and instead prefer to enjoy a given builder's/manufacturer's original intent and execution of a product. If it turns out not to provide long term satisfaction, I find a way to trade out or up to another piece of original gear. And repairs to restore as originaly designed are the only way to go. Mods, no matter what they are, reduce long term resale value. Also, I would always want to know if a previously owned product was modified so that I can steer clear of purchasing it. I have had a couple of bad experiences in this regard and won't purchase modded gear ever again. In fact, there should be a policy that if an Audiogon member sells a piece with undisclosed mods in the offer for sale, and it is determined by the buyer upon receipt that it was indeed modified and undisclosed prior to the sale, then the buyer should have the option of a full refund and return, NO QUESTIONS ASKED!!!

I had no interest in mods until I heard a friend's GNSC modified ARC SP-14.

Reminds me of the saying about 'fools rushing in.....'. I find it amusing to see folks who immediately have a unit mod'd when they haven't even heard it and how often mod'd stuff appears in a for sale ad just after a mod is performed. And, concurrently how seldom we ever see an professional, or even user, A/B analysis of the performance differences.

I agree with Ptmconsulting. Don't mod unless you KNOW what the result WILL BE, not just what some merchant tells you. And, FWIW I would never do a 'mystery' mod, or a mod which is not reversable unless I had actually heard and actual unit in my system in my room. Caveat emptor.

I would respectfully disagree with Ptmconsulting. There is only one type of mod, and that is where the actual circuit paramaters are altered. Substituting a different quality part of the same value is referred to as an upgrade, not a mod. Although many of the modders take liberties by calling upgrades mods. Confusion in the service of marketing.

There is yet a third category of work, restorations. With a restoration NOS parts are used to replace worn or out-of-spec parts, the idea being not to make the piece sound better, but to return it to its original sound.

Nothing wrong with any of them in my book, the problem with all but restorations being that many products are voiced, and this will change the voicing of the product. You may like it better, and you may like it worse. Then there is always the value issue and some of these things are good value, and some not. Some will increase the value of a product, and some will decrease it. It's somewhat of a crap shoot.