Sorry if this has been talked about before but my search of the forums returned no hits. I have a 90 GMC Sierra 5.7l with stock exhaust. She has a hole in the muffler and it needs to be replaced. I am not a mechanic by trade but I do most of the work on my truck. I want to try and replace the muffler myself. I have read about using muffler sleeves. My exhaust pipes are good. What do ya'll think about using the sleeves? How hard of a job would it be to change the muffler? To me it looks pretty easy. But I'm not sure on using the sleeves or if I should just take it to a muffler shop. Money is tight. Thanks.