New Component Upgrade Success Rate

I have found in all gear digital may be the only exception,  you buy a good piece of used gear and have it modded . I have worked with technicians gor some 20 years now  and what most people donot realize their  $5k preamp for example has less then  $1000 of actual psrts inside, and parts quality average at best. 
Capaciyors, resistors wiring, transformers and other parts  , even thjngs like gold plated copper Teflon tuse sockets better connectors and copper iec input 
Noticeable sonic improvements 1500 in upgrade parts would make your used 
Amp,preamp a close to  $10k product  like putting in a Nascar engine in your family car.it is cumulative . I have a Pass labs F6 build with A Nelson Pass 
Schematic he allows and just made it a dual mono in one chassis incredible results ,  find a well respected tube preamp and have it rebuilt ,same with speakers redo the Xover night and day results. From $10 stock Solen capacitors to Premium  VH caps Audyn ,Jupiter, Mundorf for example.if you have any specific questions drop me an email.good luck.

I've had two new items returned in my journey so far because I could. Others were sideways improvements meaning different not necessarily better. These items were bought used and I stuck with them but that was a good thing. It helped to get the experience learning what different gear sounds like. Some things I'd like back and won't forget em. I've had much more of a rewarding experience tuning, tweaking, learning it's not always a component right off the shelf new or used that's gonna get me there. I would say my "success" rate is damn near a 100% percent because everything is a learning experience. The one true surprise/failure was my one experience with a mc. Nails on a chalkboard to my ears. That was through a step up into my Quicksilver. I didn't even think it was worth trying to work with it. I will try again with something else. The other surprise was a 2k ss phono that was cool but the heavens didn't open up with a choir of angels either. Gonna just enjoy the music now for awhile. It's not perfect but I know it's weaknesses and its strengths. The Decca super gold whispers in my ear at night tempting me from Grado though. 

I like to try a new component once in a while when the upgrade bug hits. 

I am sort of beyond trying new flavors of components just to satisfy an upgrade bug.  As you are finding out, as I did years ago, the actual improvement with electronics and peripheral items like cables is only very slight.  If at all.  Its the transducers in a system like cartridges and speakers that will have the biggest sonic impact and I am pretty much where I want to be with these.

Much better to analyze where the weak links are in a system and address these.  I am having a harder and harder time finding them in mine so I guess I am done for awhile.

"Much better to analyze where the weak links are in a system and address these."

You hit the nail directly on the head, pananeer.

Best to you,
Dave

My rate is 90% as i know what i am doing don't rush into upgrades without hearing them in my system first this is the key.Good luck with your next upgrade.