You can access all the GP's without removing the intake, you just have to take your time and wiggle your hand under there. The bolt size is eaither a 6 or 6.5 mm. If you want to remove the intake manifold, you will need to remove the fule lines first, then all the stuff that is bolted to the intake. make sure you lable the lines, they look very similar in lenth.

Good luck.
I am actaully removing my intake next week, since it is weeping slightly and I am very anal about having any seepage on my spotless engine.