Fender Jazz Bass Pre Slotted Nut

I bought these because of (1) low price and (2) the fact that they were pre-filed. I knew nothing about replacing a nut on a bass, though, and found that I was able to remove the old nut but was not able to get the new one in so easily. I thus brought it to a repairshop who finished the job for me. The set-up of the jazz bass is now better, the sound quality didn't really change - or at least I can't detect any of that.

So if you're not so used to fixing/changing things on your bass, you're probably better off taking it to a shop to get it done as opposed to taking the DIY route.