I traded my 01 for the 03 for mileage reasons, plus I wanted something i could make a little faster without all the extra weight. both trucks where 4 x 4's, extended cabs. the 01 had a 6.0 the 03 has the 5.3, both have about 40K miles. I don't think I got screwed. Did I. what should my first mod be to my 03, performance wise. It is a virgin.

 

Nelson performance tune, CAI, long tube headers.

 

If you have the money, do 6.0 swap.

 

To keep your gas milage up I would just do a really good cam, long tubes, 3000stall and tune the hell out of it. I did something similar and my gas milage never changed once we got the LTrims worked out which was pretty easy if your tuner is local.

The 6.0L is a gas hog so I don't know if a swap is the best idea.

 

thanks

 

I would recommend a Radix blower. More performance improvement than with any other single mod, very good street manners, and gas mileage stays essentially the same as long as you keep your foot out of it. Drawbacks are it is expen$ive (~ 6K) and you have to use premium ga$.