Go the Blue.. Bayside blue isn't hard to match at all.. Providing you buy it from the same paint shop/company and get the same person to repaint, shouldn't be a problem. Believe it or not, yellow is actually harder to match.
I believe you would be looking around the 4-5k mark for a decent job (outside, jambs but no boot, or engine bay). But you could get cheaper from a backyarder if your not too fussed on finish.
It will also be cheaper to paint the gtr front before it goes onto the car, as most of the time it is painted off the car, then assembled.
Good luck with it all