I know this kind of subject has probably been beat to death, but I'm wondering how much performance gain can be obtained for the 2004 5.9 H.O. before durability and longevity to the engine as well as the driveline starts being compromised? Most likely I'd just get a module or programmer, but reliability is of supreme importance, more so than some added power. That being said, if I can get some added HP without sacrificing drivetrain life, gitty up! Thanks in advance.

 

100 hp seems to be the magic number before the auto tranny starts to be a liability, less of an issue if its a manual trans

paul

 

Cool. I guess I can shoot for 50-75 HP increase with a little peace of mind. Thanks.