I was with you up until here. Asking respectfully, $300 to $400 on what repairs and upgrades?
And what are you comparing it to after the repairs/upgrades? Are you implying that MIM's and Ibanez need the same repairs/upgrades? If you don't mind, please clarify.
1. The biggest difference is leveling and crowning the frets. . . I've been doing PLEK, but previously was doing it by hand. I like to run my action ~.085" @ E string and ~.080" @ G string. To get there cleanly on an off-the-assembly-line instrument I've found is really lucky. The SX's have way more funky surprises going on fret-wise than others mentioned (there is mention a couple times on this thread of folks pounding down a fret or 2 to make it work), but if you're going to level them anyways, it doesn't really matter. . . save the money on the front end.
2. Shielding and electronics. . . while the stock pots/jack work, I have to remove them to install foil shielding, so I just put new ones back in. Many of the SX jazz basses will not fit full sized pots without routing the control cavity for clearance.
3. Neck shimming and threaded inserts. I'd say about 8 out of every 10 SX's need to be shimmed in order to run low action. . . a simple change in the neck pocket spec (cut shallower) would skew those figures favorably, but it seems at this price point (My wild guess ~$60 ea. at wholesale), there's not much that can be done about the labor force or process by which these things are assembled. The neck screws on the SX basses are sort of randomly hand drilled, so necks are completely non-interchangeable and the screw hole paths crooked. The neck pockets are a roll of the dice. I found that installing threaded inserts yields a non-trivial improvement in sustain and punch, so I just install them as standard . . . unless the client is really short on cash and I'm doing bare minimums.
4. Pickup/Neck/Bridge alignment. . . Fender has this problem as well. Many times, these don't line up properly and I end up plugging a bunch of holes and re-aligning things (pickguards/bridges/neck) which saps a lot of time.
5. Pickups. . . So far, I seem to be the only person who finds this a problem, but the SX pickups distort when hit hard in a very harsh way (P and J pickups). I call it the "SX effect". Feathering the intensity especially when slapping minimizes the effect, and if you play under the threshold, the basses sound great. . . exceed the threshold, and "SX effect". I change all the pups out now. I'm using custom developed Nordstrands.
SX effect:
6. Nut. . . I keep stock nuts on when they work, but they are often hacked up straight from the factory. When that is the case or when someone request it, I cut a new nut.
7. Strings. . . choose your weapon. .. . most anything you pick will be better than the factory SX roundwounds.
Add all that up for parts and labor, and you get into the range I was describing for costs. Do a bunch of it yourself, and you have a great deal on a sweet instrument. In my personal opinion, the really, really good SX's can go toe to toe with anything out there when finished in terms of tone and playability and that's what I compare them against. . . F-bass, Lakland, Lull, Fender. In all other respects (fit, finish, hardware, etc.), they are still "just SX's". When all the above mods have been properly executed on an SX, it does not feel, sound, or play anything like it did when it came out of the factory box.
MIM's and Ibanez's will not absolutely require all of the fixes and mods. . . but most of the mods still produce significant improvements over stock. Stock MIM pickups don't have "SX effect" and neither do the stock Ibanez ones, so they don't need to be fixed. Stock Fenders are shielded, but for whatever reason, the shield system does not work as well as a properly grounded copper foil shield job along with proper grounding on the electronics. Neck joints on factory Fenders benefit the same as SX's though from threaded inserts.
These of course, are my opinions, and a lot of people are perfectly happy to leave it all be and just play the stock SX. I started immediately finding things wrong with the 1st SX I owned and immediately took it apart to fix the problems.
