Come on why is that when ever someone talks about a aftermarket part its "bye bye warranty". You could buy a billet grill cover and if something goes wrong with your truck ford will say its because of the grill cover or exhaust perhaps your keychain..... whatever u get the picture. If it leaves no trail like the plug in programmers or k&n filter there is no way for them to say that u had these thing on the truck. What are they going to do back track your credit card records to see if you ever bought it. Dont think so. Now un less the propane leaves a diffrent burn coat on pistons then thats a diffrent story but i do not believe it to be like NOS. Dont mean to bash the warranty thing but what ever you put on your car/truck you can take off just as easy.

Sorry for the vent tn mac