I have a MP112 that I am putting on an 07 NNBS with the 5.3. I plan on putting headers, small cam, cai, etc. For comparison, does anybody know the pro and cons for going with a 3.3 or 3.6 pulley.

 

the 3.6 pulley will make less boost. The 3.4" came stock with my blower for the 5.3. I now run a 3" pulley and make 10lbs+
It's usually recommended to start with the stock pulley and then upgrading after all systems are checked out. As you increase boost it will put much more demand on your drive-train and fueling systems.