1. the block doesnt need to be bored out. and even if you're using a b20 block, the head doesnt need to have the combustion chambers modified either.

2. the b16 head and b18c5 heads are from the same cast, they are practically the same except for the ITR is mildly ported. If you throw ITR cams, valves, springs, and retainers in a b16 head and polish the runners yourself, you'll basically have an ITR head. the only real reason to use the GSR head is if you have one lying around or can get it cheap.

3. just incase you were going to try to reuse your headbolts, you'll need vtec head bolts so you may as well go with the arp studs while you're already ordering their 8mm rod bolts