I just got a (email) newsletter from Cummins. Never got one before
Anyway, here are two questions of interest in the faqs section. I wonder WHO determines if the damage was caused by an enhancing device?
Maybe you guys have seen this before, but its the first I received.
Will I void my warranty if I use any aftermarket performance-enhancing devices?
If you use any aftermarket performance-enhancing device and it is determined that the device caused damage to the engine, drivetrain or vehicle then, yes, your warranty would be voided for that damage.
Does DaimlerChrysler authorize the use of high-flow aftermarket air filters such as K&N with my Cummins engine?
No. DaimlerChrysler and Cummins do not recommend the use of increased-flow air filters such as K&N because they can allow contaminants into the intake that can ruin an engine (scoring the sides of the pistons, etc. ).

Maybe you guys have seen this before, but its the first I received.
Will I void my warranty if I use any aftermarket performance-enhancing devices?
If you use any aftermarket performance-enhancing device and it is determined that the device caused damage to the engine, drivetrain or vehicle then, yes, your warranty would be voided for that damage.
Does DaimlerChrysler authorize the use of high-flow aftermarket air filters such as K&N with my Cummins engine?
No. DaimlerChrysler and Cummins do not recommend the use of increased-flow air filters such as K&N because they can allow contaminants into the intake that can ruin an engine (scoring the sides of the pistons, etc. ).