Yes, everything needs to be at 0. No, one drive isn't enough for a retorqure to do any good; Generally, 5 to 7 full heat cycles (start the car when cold, run until it's at normal op temps and then drive for a while, then let cool completely... repeat.). With the fasteners this only needs to be done once when they are new and ARP says it needn't be done on studs... but it's cheap insurance, especially when dealing with components which do crush like a composite HG.
Heh, I used to always tell people not to be nervous.... I've done a couple of these now... but I've been working on upgrading to a 2mm MHG and what should have taken two days has now been going on for two weeks. It appears to be a wiring harness issue... I've had a couple local guys I know who know these engines as well (if not better) as I do come over and they're of the same opinion.
I'm off to start testing the harness today....