Is it wise to drill a 1/8" hole in each muffler in my 2006
grandprix gt to allow water ans moisture to drain
Not wise at all. you don't want any holes in the muffler, you won't pass inspection with one. Drive for at least 10-15mins at a time, short trips kill exhaust systems.
Longer drives will warm up the exhaust system to the point where the condensation will evaporate on its own.
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