Ok, I have a whole bunch of questions to ask. First off, I own a 03 305/555, 3.73, and have recently put BFG 315's on it. I have noticed a little bit of power loss due to tire size increase, can be compensated by shifting at higher RPM's. I would like to have more power but relatively safely. I want this truck to last quite a while, with as little maintenance as possible. I have done some research, and the first things I would like to do are exhaust and intake. So here goes with the questions. Will deleting the muffler cause a loss in power? And will doing exhaust without intake be an issue? Also, is there really that much of a gain in going full 4", or can I get away with the 3.5" straight pipe? Now to the intake, I want to run a cool air box, not a BHAF, but don't want a oiled filter. I have really liked what I have heard of the Scotty product, but can it be ran with a different filter? I can't afford intake right now, so are the holes in the bottom of the stock box a good idea or a waste of time? Ok a couple more, get it all done in one shot. Now boxes, Edge juice or TST, don't want pressure, but want power. Does the juice have a dangerous amount of pressure? And if I am thinking box should I be thinking push pump and new clutch? Sorry for the length, would appreciate any help, thanks.

 

I would say with the mods you are looking at it would be safe to use a 3.5 inch exhaust, and just about any intake would do just fine. the holes I had a 99 cummins before my new one and i had holes in the air box. In the winter it tended to clog up with ice and snow. if you do not want insane power and want to keep everything together i would choose the juice w/attitude or the hot juice. My only concern with the tst is it seems to be a bit jerky with the power, it runs like a raped ape if you are in it, but the second you let off the power is gone immediatly. the egts also get a little hot with the tst, however I solved this by putting a B1 and i rarely hit my alarms for egts. the clutch and fuel system will probable have to be upgraded after around 120hp. the engines seem to miss out above that without a fuel system. good luck with your ctd