Is there any point in removing the air control valve? Does it improve performace in any way? I have no cats or airpump so I'm not gonna pass emissions at this point anyway. I've seen a blockoff plate that you can buy for it for like $10.

I always like to remove whatever I don't need. You're not really going to gain anything by removing it, but it will help clean things up. If you ever want to make a custom secondary rail you'll probably have to remove it.