I was told to improve my MPG I need to upgrade my exhaust,intake and tuner. My question is which exhaust should I use?
Will it make a difference if I do it from the catalytic convector out or do I need to run it from the turbo down. And for the intake and tuner what do you recommend?  

get any 4 inch turbo back exhaust kit you want

then get a tymar
http://www.superdutydiesel.com/wiki/tiki-read_article.php?articleId=38

then get a tuner
http://www.dp-tuner.com/  

I just saw the link you sent me and it awesome. Do you think the filter idea will work on a 2007 6.0l ford350? If it does do you get the same performance you would get if you bought a new one. This is a cheap way to go. thank you.  

well ask aroundPSN and see if they have any info but if they don't you could go with anS&B filters just stay away from the K&N filters they let dust in  

the new afe dry filter is really good as well i just put that  an edge evolution and banks 4" turbo back exhaust on my dads 06 dually and it gained him 2-3 mpg. just depends on if your lookin to hot rod your truck or not, if so you probly dont wanna use something like the evolution but if all your lookin for is mileage and a little more power with a trailer behind you it is great setup  

Did you run the exhaust from turbo down or converter back?  

from the turbo back and delete the cat it will kill your flow and sound i know most exhaust companies offer a cat delete pipe i strongly recomend getting one as well  

also putting on the bigger downpipe will help keep your EGT's lower  

In other words get rid of the cat and just run from turbo back right. Is that what you mean. Is this legal. on the other hand if i run from the cat back will it lower my  EGT and get good sound?  

I live in CA and thats why am trying to inquire from cat back to avoid failing smog test.  

oh ya if you live in ca you will definitley need to leave the cat on because you wont be able to pass the smog test. i dont know how strict they are on the test or how often you get tested on it but i have mine set up so i can put the cat back in if i need to then take it back out. that might be something to think about as well. but i would still recomend putting the bigger down pipe on mainly because of the egt's and it makes a big difference on the exhaust flow. with the banks kit i put on it shows you how to cut the cat to make it fit with the exhaust. are you planning on doing the work yourself or having someone do it for you??  

My dad bought the Diablo Sport for my duramax when it was his truck and with the cold air and just stock exhaust he managed to get about 26 to 28 out of it. I dunno what it does for the powerstroke but i think it might be worth lookin into.  

damn thats pretty good mileage if thats truew im gonna take the six gun out of my truck and run that id probly never get even close to that kind of mileage tho mainly because i cant keep my foot off of the big pedal on the right lol  

I am planning to do all this my self.  

ok just to help you out a little if and when you gert your exhaust and if you  do go ahaed with the turbo back exhaust dont try to get the stock downpipe out in one piece. get the sawzall out and cut it in half it will make yuor life much easier. and save a lot of time