I run glass packs with the glass all knocked out of them. Yes very loud, and I wouldn't have it any other way. Oh yeah, they exit just past the cab. They really get loud at full throttle while kicking it, but I can usually rumble past the pigs without much attention. It's definately not something I can drive after drinking very much though
Just take a 1" drill and start going through the center of the mufflers (this also works well for those newer vehicles that are required to have cad. converters)