I can see some cases where some mods could and maybe should void the warranty but the dealers that look for a reason not to warranty a car are only shooting themselves in the foot in the long run. I bought a new Ford F150 in 98 and I lived in a fairly small town then. I ordered the truck with a 5 speed and the trailer towing package that was rated at 8500 towing. The truck was never modded or abused and the 5 speed had problems from day one. The dealer attempted to fix it twice under warranty with little sucess then when I brought it back the third time the service manager said he was going to void my warranty because he saw me pulling my race car on a trailer and I exceded the towing capacity. I explained that my car (Fox bodied Mustang) and trailer together wieghed 5K which was well under the trucks tow rating. He called me a liar so I contacted Ford Motor Company about the warranty issue and they said they did not care and would not help me and I was on my own. I traded in the F150 at the GMC dealer and sold the Mustang and traded off my wife's Cobra convertible that we bought new and I have not owned a Ford product since and I will not own one ever in the future. I got a Ford Service survey right after that and I let them have it on the survey and 3 months later a rep from Ford called and said that he wanted to "make it right" and I told him he better go to the GMC dealer and track it down!
