I want to have a punchy/meaty (Geddyesque) fretted J bass for most rock styles and a singing fretless for jazzier work. I don't know much about how different mods will affect tone and playing. Any helpful advice on tonewoods and mods would be appreciated. I do know from reading other posts, that the SX and Fender JB necks have different heel sizes. Not an easy swap out, and possibly not worth the effort to swap out. I've two basses to use: MIM Fender JB DLX - Alder bod, maple/rosewood(f-board) neck, All stock parts. P-Ups are great and the Active electronics can produce a very wide tonal pallete, though it never gets as much sustain and laser tone. Bridge is old stock stank. SX JB 75 style - Ash Body, maple/maple neck with black inlays. one mod only; BadAss II bridge. The SX has great sustain, it rings well and sorta can sound in between the Marcus Miller bass and the Geddy. Great treble and mid-range response. The bassier response is a little "woofy", but it has punch and sustain. I suspect most of this is from the heavily laquered maple fretboard and the BA II bridge. Maybe some comes from the lighter Ash body. High G-string notes sing for days and upper register chords/double stops sound clear. It's not as thick as the Fender. The Fender is "thicker", but it is also strung with heavier strings. If the SX is a radiant Orange in tone color and sustains like a laser, the Fender is a deep red or burgundy and has more of a "thunk" to it. I don't know how neck swapping will effect these basses. I need to setup the same strings on each and compare. Will switch back to Rotosound Swing bass for both maybe. First Mod Option: Fretted Punch Bass - Move maple/maple neck of the SX to the Alder body of the MIM JB Dlx. Transform it into a Franken-72 bass or Geddy bass. Also move the BA II bridge. I would prefer active electronics on the rock bass for more tonal control. Also, the Alder body/Maple fretboard is the combo used in the 72 Geddy sig bass. The Alder gives it deepness and the maple adds britghtness and sustain on top of it (IMHO). Fretless - Defret the Fender Maple/Rosewood neck and bolt it on to the SX Ash Body. No need for as much tonal control on the fretless. Maybe singing solo to uprighty and that's it. Also curious as to how a maple/rosewood neck/f-board will sound on an Ash JB body. I was hoping for something more cello like. Second Mod Option: Fretted Punch Bass - SX with new p-ups and maybe new wiring. The SX electronics are sometimes noisy when changing tone or volume. Not as much tone control as the Active JB Dlx. Fretless - Defret the MIM Jazz Dlx, and install a BadAss II on it. Thanks! I searched and read other posts, but none addressed the tonal needs I am seeking to achieve.