Join Date: Jun 2006
Location: Sierra Foothills, California
First off, glasspacks are very oild school. If you want a free flowing exhaust, there's better choices.
If you insist on glasspacks, be advised there are 2 types. One is the louvered core, the other is the perforated core. Grab one and look down it's throat. Do you see little dimpled louvers from the center tube sticking down into the flow? Or do you see a smooth wall center tube with holes (perforations)? The louvered core versions don't flow for crap, those louvers sticking down into the flow provide a lot of back pressure. The perforated core versions flow much better.
Which brings us to a better choice, which is a Magnaflow muffler. It's a straight-through perforated core design. Very well made, they sound great, and flow very well. Better than Flowmasters.
Go under your car and measure your existing muffler. Then go on Magnaflow's web page and find which model number of their's is closest in size to your OEM muffler. You can then order the thing on line and save a wadd of cash, and then just take it to a muffler shop and have them weld it on.
I have an 88 IROC Camaro with a Magnaflow, it's great. Pretty mild mannered around town, but loudern'hell at wide open throttle. Best of both worlds!