Just got back from a long trip and found a leak at the base rear cylinder. Took it to my dealership in Vegas and they will cover it under the ESP warranty but service manager did tell me that Harley was asking about mods and specifically the tune. The bike is a 16 cvo limited with the twincam stage 4 117 and rineharts but I run the Harley street tuner. I know the manager so not a concern at my local dealership but it looks like Harley is being quite strict with performance pipes and aftermarket tuners. it appears they have had issues with the M8 stage 4 upgrades and Harley is asking the dealer to check the tune. I have the 7 year ESP warranty and just correcting this cylinder leak would have been a chunk of change (along with other warranty issues I had before) so the extended contract certainly gives me peace of mind. I don't want to deal with Harley if I ever need major work done at any dealership so thinking of switching back to stock headers. So just an fyi on the Harley warranty