What the difference between the factory y-pipe on my 2000 Z28, from an aftermarket 2.5" y-pipe? Let me know anything. I want to upgrade, but I'm not sure if it's worth it. Thanks.

the pipe diameter is probably a little bigger, but also, where the second pipe joins the forst, is a lot smoother merge point. some y-pipes jsut have a normal pipe comeing from one end of the motor, and the other pipe is jsut welded in from a 90 degree angle so it creates turbulence. an aftermarket y-pipe joins the two pipes in teh same direction, so the airflow is a lot smoother, thereofr making more power.

The stock LS1 y-pipe is flattened out on the drivers side, this causes a restriction. My advice though is to get headers along with the y-pipe, this will give you the best gains.