hedman "tight tube" hedders?

Bringing this one back because it has some excellent info. Just got me some headers because ANYTHING is better than the crappy ones that are on the car now. Car is only a 318, so wouldn't 2 1/4 piping be adequate? If they have to use the older bender and not mandrel bends I would like to stick to 2 1/2 so it doesn't get too constricting, but I think going slightly smaller diameter might help a little with fitment - especially since it's just a 318. Opinions?