brucetopping

Trying to replace water pump on '07 Mazdaspeed 3. Belt is still on. Of course pulley just rotates if I try to loosen the bolts so I used 2 wrenches, one to hold one of the bolts tight in place and the other to loosen the bolt - BUT I'm finding the bolt is starting to become damaged like I'm stripping off the edges of the bolt. Seems like they're over tightened. I'm wondering if the shop used impact tool and over-torqued them. Doesn't seem like these should be ~ 100 lb ft.
How did you get your water pump pulley bolts off? I've looked around YouTube and haven't found any tips.