Just on the whole mexican debate, I went to a music shop the other day in Norwich and they had two Mex 60s classic jazzes, one black and the other sunburst. I first tried the black one and was utterly dissapointed, it sounded muddy, undefined and generally quite poor. Also the neck seemed a bit over tinted and a bit too orangey. Next I tried the sunburst expecting the same but to my suprise it sounded absolutely killer, an almost perfect jazz tone, and the neck was a much nicer shade.
What I don't understand is how two basses of exactly the same model can sound so different. I'm obviously not linking the colour to the tone in any way but the mex models do seem to be pretty inconsistannt in quality. I guess the answer to the problem is try before you buy. And also don't hold prejudice against any kind of bass until you've tried one out, it really did suprise me how nice the sunburst one sounded.