To upgrade or not to upgrade

Hey all.

I recently scored a great deal on an Ibanez Sr706 bass. I originally bought it to flip it but have decided to keep it and use it.

My dilemma is what to do now. I have nordstrand pickups in my other bass. Considering switching to nords in this one too. Anyone done this upgrade from the bartolini mk1 to nord big singles and if so, what kind of difference did you find tonally?

Additionally, is it worth upgrading the preamp?

Thanks fam.

Pic for fun.