I am looking at converting to true duals with dual cats and flowmaster 40s. What size pipe should I use? I have heard go with 3" if single exhaust and 2.5" if dual. Does this sound correct? I just need to order the right cats/mufflers. Brian Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!