About the rosewood thing...
It's more likely that you will hear the difference in the rosewood if you spend a lot of time in the studio. There is a subtle difference in sound between the Indian, Honduran, African, and Brazilian rosewoods, but I doubt if you would hear it that much in live playing situations. There are three reasons for the attraction of the Brazilian rosewood:
1. It's hard (almost impossible) to get.
2. It is "authentic" when compared to early fenders.
3. It feels a little different.
For my purposes, an Indian rosewood board would have been more than good enough. Two factors weighed in to my decision to go Brazilian, I wanted a Brazilian board before they became impossible to obtain, and I have had a couple of opportunities to play Mitch's LG5 and I love the feel of his board. Toss in the fact that I consider 3TS to be the "signature" Precision look, and you have my reasoning for ordering a KBP5 with 3TS nitro, and Dalbergia Negra.
To be honest, I doubt that I will ever fully appreciate the subtle sonic flavour of the Dalbergia board, but the unique feel and "cool" factor will be there every time I pick the bass up. I guess I have to admit that I am a little more swayed by the aesthetics than the acoustics.
Any way you go, rest assured that your AC bass will be a marvelous looking, feeling, and sounding instrument. Don't obsess so much about options; spend your time figuring which options fit your budget best.