Just too start with, I modded my HB P bass with SD QP's and pre made CTS wiring and new hardware, the same with my SX Jazz with Diddario's and again pre made CTS pots, wiring and hardware, so just straight swaps, both are fabulous Basses now, well too me anyway.
I have a Harley Benton MP-4MN, love everything about it bar the mounting issues with the electrical side of things, had to re solder pots on Pup selector and a few other joints as lots of dry joints and poor wiring, even with this done the sound distorts now and then, the volume crackles on and off too, been in touch with Thomann and worked on the suggestions they have made to no avail and apart from sending it back to be sorted, which is a pain, and if I am honest with the current standard of work and components is anything to go by I will have the same issues again at some point.
I love the feel and the Quality of the bass, the way it looks and the way it plays, so its ripe for a modification, tired of the Active stuff as the rest of my basses are passive so would like to make it straight passive, I would like to change the Pup's which are P Bass and Humbucker, however I would not know where to start apart from buying Pots and Pup's, the electrics side of things bar soldering it all together stumps me completely. Also could I buy P Bass pickups from one manufacturer and a Humbucker from another without any issues of compatibility, can I get a custom wiring loom made somewhere, lots of questions/issues so any help would be great. Thankyou.