Leon - I just replaced my headgasket and stuck with the stock bolts. If you are going to turbo your car or use NOS, then it would be a good idea to get a set of ARPs. Otherwise, just replace your stock ones and they should be fine.
I believe there is an archived post on what the specs are for the ARP bolts. Can't think of it right off hand though.
Sam Crawford Blackbird NW.DSM.ORG
97 Eclipse GS-15.463@88.57MPH - RIP 92 Talon TSi AWD-12.927@105.47MPH