Fake "NBD" thread-the Sonic Bronco bass did change quite a bit with the DiMarzio Fast Track 1 (DP181)! I had DiMarzio make me one with the "ugly" purple that suits me quite well-wish it were truly violet, but it's fine. It's my own weird bass, for an even weirder player.
There is a personal connection/life story to the colors, so everything means something to me in this little bass.
The character is fuller, slightly less air, but not overly compressed sounding, with nice clarity. Better mids/low mids (not just the strings, which do have nice mids by themselves.) The dynamic range was improved despite the openness and air of the stock pickup. But most important of all, it's my quietest pickup in my collection-absolutely no noise, so my more potentially noisy pre-amp settings and pedals work like a marvel without much if any concern. Even if it sounded worse, that alone was worth it, but I feel it now has a much closer character to a "modern" P bass sound than stock. The stock is NOT bad, airy, but can it hum (sadly.) I prefer the mids/fullness of the Fast Track 1-medium output, not too hot. Pickup can be quite close to the strings for a nice place to play finger style, as the magnets aren't too strong.
Having this experience, I do have to say that going "thicker" with the DiMarzio choices may be precarious, and better suited for a darker guitar tone-on bass, it may be too much. So despite the DiMarzio graphs on their website, remember these are relative to the intended guitar voicing-some of the options may be too muddy (though a player may like that!) I think I could have gone slightly thicker, but not by much before losing the balance with the mids and highs. So I do think the Fast Track 1 is a safe, "bass-sounding" drop-in choice without being too overwound and then losing too much clarity. Excellent ceramic pickup from DiMarzio as usual (not all ceramics are the same.)
The gentleman that installed my new 500k pots, jack, and pickup also cleanly fixed my few "sprouty" frets which I mentioned when I first acquired the bass, last year. Also, made it so the newer pickguard is straight, despite the few factory angled screws (before, the pickguard warped a little-surely a bit my fault, no doubt! But the angled screws were annoying. EarlPilanz's pickguards are GREAT.)
(Mr. Wong on YouTube had trouble installing Gotoh Resolites on his Sonic Bronco-though the USA Hipshot 3/8 Ultralites tuning machines/Xtender have the same measurements as the Gotohs, in my case they fit with just slight pressure. Perhaps I was lucky with my version of the bass? But some of you have installed them as well. Very confounding, and not meaning to speak ill of that gentleman.)
(Anyone knows of good custom knobs? The ones I got for it are just fine-the stock ones did not fit the new pots, as I had unwisely not taken into account.)