I got bolts five, six and seven replaced on Mission Impossible over this last trip. As of now, bolts one through eight are 1/2 inch A.S.C.A. stainless steel.
Alas, I may however have created a problem. With my tongue only partway into my cheek, I wonder if a climber will get on the route, love the big, solid and new-looking first eight bolts and then look at those above and bail? I hope not, it's a fine, fine climb.
I doubt I'll do any more replacement on this though. Gavin and I finished the route we were working on next to it (Get Smart 5.10a ***). Both of us marveled at the quality of this new line. So did two young guys who, walking by as we finished it, asked if they could climb it. They did and confirmed both the grade and the quality (and that's with a lot of the moss still in place - although not really on the holds that are needed - not all of that moss will remain there in the coming months).