Megan Racing full exhaust system

I just bought MR headers, test pipe, and cat back system. I was just wondering if there is any thing i should know before installing. I have to buy some heat shields and spring loaded bolts....do local auto parts stores carry that stuff or would it just be better to buy it off the internet?

P.S. I know about the O2 problem and i going to atempt the defouler trick.

Thanks

Also does anyone know the torque for the bolts to the head. (hot and cold)