going oversize will also hurt power.

i only have 65 hp injectors and i have five inch and i can tell i have a little more horse power than with 31/2 inch exhaust.

Yes you have more power than with the 3.5" because it is restrictive. If you go to big it does nothing for you.

if I remember correctly 5" does nothing for people till your over 500hp

I need to find the article from Diesel power mag but that is what they were saying also.

I thought you have all the back pressure you need from your turbo got my 5" expandit from dieseldawgs it was only like 30 bucks more than 4" took me literally an hour to yank out my old exhaust and bolt the new one up and what a difference on power from the stock straight pipe. and love the noise.

the bigger the better it sounds if you ask me

5" has a deeper tone than the 4"

I'd like to go with bigger injectors and maybe get a stock Turbo off an 03-Newer 3500 or something. Like I said just upgrade here and there "Budget Build" basically. I just don't want the exhaust to be to restrictive but I don't want it to make me lose any power either.

Does anyone know the specs of an 03-Newer Turbo? Also, what size injectors would compliment it the best?

an 03 or newer turbo is a very small limited turbo it's either a 58/59/8 or a 60/60/10 or 9, not sure i've heard different things from different people