i replaced them many times on non-boosted motors without any problems, but since i took apart my boosted b18 and used the headbolts its leakin oil out of the side of the head...

 

Well over here in Europe the Honda Dealer says that the head bolts don't stretch
And they said you can reuse the ehad bolts, well at least on the ZC then...they never have head bolts on stock.

 

you can reuse oem head bolts. i've done it several times, and all the techs here at the dealership say the same. i think it's more a matter of preference by the builder. if you want to replace them, go ahead, if not save $80 or whatever they cost.