Wow, lots of good and not so good advice so far.
My Opinion:
1. Is your friend going to upgrade an existing system or purchasing a totally complete system altogether?
a. If upgrading an existing system, then my advice is to go one piece at a time slowly.
Here's the deal. Is your friend desiring to be a "listener" or playing music as background music while doing something else.
a. If Listener. That means taking the time to sit for sometimes hours and really listening to music. So, ask the question. What sound is your friend looking for? Completely accurate? violins sound like real violins, pianos sound like real pianos, etc. not electronic substitutes? This is really important because it helps to establish a budget for the particular system or particular piece to be replaced/upgraded.
Take the time to determine what sound you are looking for first. That means visiting many friends with decent systems, visiting many dealers with decent equipment and just listening to your favorite music on those systems.
I am a big advocate of when visiting high end stereo stores going to the extremely expensive room first and listen to the absolute best system you can playing your favorite music. Listen well and ask yourself what am I hearing on this system/equipment that I have not heard before. Then go listen to equipment within your initially established budget and play the same music and ask yourself what is missing here?
You want to get as close to "being there" as you can as affordably as possible. This takes a lot of time and patience.
Establish a relationship with a few dealers/stores. Get to the point where they know you are serious and will allow you to take equipment home to try in your home. Many will take your credit card information and let you try at home. Return it if you are "there".
Purchasing and trying at home only to find out you aren't "there" sucks.
Any dealer worth their salt selling expensive equipment should let you demo at home first. If they won't or don't have a no questions asked return policy with no restocking (stupid) fee, walk away.
So, what sound are you looking for and how accurate. This helps establish a budget. Then go look at equipment within that budget.
I would definitely recommend purchasing top of the line or near top of the line used equipment. Equipment that was discontinued but was top and replaced by something new from the manufacturer. You are getting some of the best that compares at or better than most new equipment for much less. I know, hard to demo used.
But, in my experience (many decades), most changes in high end equipment from one version to another are not jaw dropping changes, but small (sometimes hard to notice) changes.
Example; A retubed Audio Research REF 3 pre-amp will outperform most new high end pre-amps today. Yes, the REF 6SE is better, but you will be extremely happy with a REF 3. Also, the REF 3 is relatively inexpensive compared with the lastest and greatest out there.
Heck, an SP 11 or SP15 is still outstanding, just no remote.
Same is true for amps, digital sources, etc.
I would let my friends come and listen and my good friends I would let borrow equipment to take home. Heck, get on Tom Wu's (Triangle Art) good side, and he might let you take a brand new piece home that needs to be burned in for a few days. It would be very hard to return it and not purchase it when you hear how good his stuff sounds in your home, and he knows that.
A/B comparisons in your home is important, switching only one piece out, making sure you set the same listening level before critical listening and then sit and listen.
What differences do you here are the exact same listening level?
Anyway, just a few thoughts.
enjoy
the entire system or one piece
