I’ve never tackled active pickups- soldering isn’t my strong point! What’s wrong with the sound btw?
It looks like a nice bass. I’ve got a GSR200 but only use it for studio work- it’s decent enough for what I need- it gets that modern sound and great for slap. I do have a sexy purple J bass though. Thinking about it, I do love that- just don’t use it much. Will post a picture at some point.
Good luck- looks like it’ll be worth it.