Hi everyone, I'm back with my impressions after playing with the Mustang PJ upgraded a few hours tonight.
My purpose isn't do an A/B test on every item, but give an overall felling of the upgrades.
Check all upgrades here:
Fender Mustang PJ upgrades
- Let's start with the High Mass Bridge:
It's beautiful and looking cool

It adds a few more sustain for sure (maybe the new strings helped??).
Anyway, it's a worthy upgrade for the price (around $50 USD)...
- USA Original Precision and Jazz Bass Pickups
Both MIM pickups were replaced with Original American made. It sounds almost the same... I said "almost". It has a higher and tighter output (maybe it's the strings again??), but the noise have been reduced a lot (noise on neck pickup is almost zero)... (My local luthier compared the noise before the ground service).
There's still a very low hum noise that stops when hold the strings... Maybe just actives pickups to stop it all.
- Pro Steels D'Addario XL EPS170S Strings
For me the big difference was in the exchange of the original strings by the EPS170S.
These strings are softer than the originals, make it easy to move your fingers ...
It sounds really cool, I hope to record a little bit for you in the near future.
I really recommend exchange your original strings with this one.
- Also, I managed to find a
G&G/Fender Short Scale Bass Case on a local store in Brazil:
Fender Mustang PJ upgrades
As you can see, It fits the Mustang, but has a lot of room.
The case is well made but it lacks some kind of straps to hold the bass on place.
There's a lot of soft foam that helps secure the bass when is closed..
It's more than enough to carry to a gig on your car/van.
It's also expensive

but we don't have too many options here
... it should cost half the price...
Next steps:
- Fender Strap-Lock (waiting to be delivered)
- Find a good place to fix the Thumb Rest
- On a near future: replace the tuners with Fender Original Mustang Tuners (the ones with the Fender logo) or a Hipshot B10 set as suggested by @Pressman52