glass pack on 5.4
ok i see the threads on expensive performance exhaust systems, but a friend of mine just had a glass pack and 3" tail pipe put in to replace the stock outfit, and it sounds great, and he said he could notice a big increase in power, and improved gas mileage, for about $60! why would i want to spend $400 on the other systems? is there something i'm missing? his catalytic converters and o2 sensors are still there, just replaced from the muffler back. you guys got any opinions on this?