Hey hey. I have a lot of posts in the Warmoth-building thread, but this post has more to do with the bass I already have: a lefty 2004 MIM Fender Jazz Bass. I'm wondering if the neck is bad, because even when I put lighter gauge strings on (Ernie Ball Super slinky), there's a pretty severe bow in the neck. Between the top of the body and the nut, it bends much like a bow-and-arrow. I have tightened the truss rod very far, and am afraid to snap it if I go any farther. Even as tight as it is, from the side profile, it appears mostly flat until the fifth fret, and starts sinking down at the sixth. Other pertinent information: I've switched out my pickups twice. First, I changed out the mexican standard-issue Jazz pickups for the American version. With the American ones, there is a warble in the higher frets, especially on the D and G strings (unless I drill the suckers down UNDER the pickguard). Next, I tried Seymour Duncan Quarter-Pounders, which don't seem to have the warble very much, if at all. Still, I've heard that such sonic malfunctions can be caused by a bad neck. Anyway. Bottom line: should I replace my neck? I've been researching Warmoth and really like their 2 extra stiffening rods idea. Does the Fender neck only have a truss rod?