Some mods are always better. John East preamp is always better than a Carvin preamp, so they're in all my Carvins. Delano pickups are always better than Carvin pickups too, so, they get swapped. Putting in a single star ground and adding shielding to the pickup cavities helps reduce noise, so I do it. Where it gets subjective is putting in switches for every series/parallel combination possible. All the combinations sound good to me. But I don't expect anyone to pay for that part, should I ever sell my basses (after all that and how good they sound, why?) If someone had already done all that and I trusted their work, I'd pay a little more.
This is where we get into issues.
Sometime around 2004 I recorded the bass parts for a CD in a real studio (my only experience doing so). I owned 8 basses at the time and brought them all. Some were really nice, and some not so much. I had tried several basses and the engineer was not impressed. He told me to whip out each one and record a few bars. When I got to my (bone stock) Carvin LB76, he was happy. He requested that I record all of the tracks with that bass.
So, your statement is ridiculously subjective. TO YOU swapping Carvin electronics is always better. Period. It is NOT ALWAYS better.
As such, we get into debates over the value of upgrades.