Originally Posted by CBRich

You guys with all this rounding really need to make sure that your socket is fully seated on the bolt. I sprayed my bolts with PB Blaster every night for a week before hand and then just before removing the cats. I used an impact swivel and an impact socket and while it wasn't easy everything did come off with no damage at all.

Here's the main thing. Make sure you do all you can to ensure you have the perfect angle before even starting to crank on the ratchet or breaker bar.