A few thoughts/concerns... Any feedback?

Volcom370Z

Ok, the first thing that has been on my mind is what size/type of tires to get. I like the idea of 275s up front, and 305s in the rear, but with a 30 profile on both, is your speedo gonna be off (RE-11 folks?)? Secondly, everyone knows that the 370 has a staggered setup. My question is, how do you determine the proper setup when getting wider tires? My guess would be since there is a 30mm difference in width between front and back you need to keep it 30mm (i.e.- if you increase the rear by 30mm you increase the fronts by 30?)?

Lastly, I've been interested in powdercoating my stock rays. I have a chicane yellow Z and I don't want just the straight black like people do. I'm looking for a unique color. My thoughts were a deep blue that almost looks black, but when the like hits it right, they reflect blue... Any thoughts/ideas?

Also, I keep reading things about what the proper temperature to bake forged wheels and whatnot (and people cracking their wheels and yadda yadda). How do I know that my local powdercoater guy knows what he is doing? What questions should I ask? What temperatures and durations should I be expecting him to use? Anyone know a good guy in SoCal?