3" exhaust???

Does anyone know who makes a 3" H or X pipe with cats for long tube headers? How about a 3" cat-back? I can't seem to find anything. My engine builder says I need a full 3" exhaust system for my 408 that will hopefully be done soon. Do you guys think that I need 3"? I also had a question on the motor mounts. Should I get solid or polyurethane? Someone said that the solid ones will make my car shake really bad. Is this true? Thanks for the help.

Thanks for the help. Who makes a 3" h or x with cats. I am getting Kooks long tubes. I heard that they are absolutely the best from everyone I've talked to. Also who makes the best link bar roller lifters and roller rockers in your opinion? I have the XE-282HR so I think that I will go with 1.6 ratio.