Thanks everyone. Because I am out of state, don't have my ranger with me, and would like to have the parts waiting for me when I get home, does anyone know what size the exhaust pipe is where the cats are? Yes I would like to keep it as earth friendly as possible while still improving performance. Also, I really don't want a constant engine light. I have found high flow cats by flowmaster but not sure what diameter/dimensions I need since I can't crawl under my truck and look right now. Also, I have found a set of headers on Summit Racing. They're Pacesetter Performance part #70-1387. They have a 2.5 inch collector and are available with or without EGR. My question about this (again I can't look at my truck right now) is do I have EGR? And is the stock exhaust size 2.5 inch or smaller than that?
Oh, and also the cats that I've found by Flowmaster are available with or without air tubes. Do I need it with air tubes?