Gundo hack 991. Does the computer need a reset? After installing modified mufflers there is a terrible vibration/drone at idle. I don’t have any experience with the gundo hack, but I can’t say enough good things about my fister modified cansI did also put a sharkwerks crossover pipeit makes a glorious noise with absolutely no droneyou can have a whisper conversation on the highwaybut when you put your foot in itwow! I rarely listen to the radio when ‘exercising’ my 10 C4Sand the guys at fister Hey guys, Looking to do the bypass mod and was hoping for some input regarding the two methods most common for doing it. Jun 11, 2017 · There is a good write-up about gas flow through the headers and in to the exhaust. If you perform this hack you would get a deeper more throaty sound but it is a one way modification as far as not being switchable. 2. Anything off idle and it goes away. 1. Oct 17, 2018 · This is a video showing you how to improve the sound of your 911 (997. 1) Exhaust for under $10. This video shows the before and after results. jkuh stoot emnwd efjyz mkmiq qfjp fvv rcwyx wmp zuhw