Tommorow I plan on going to the muffler shop to have a test pipe made. What is the size of the tubing I will need? (I have stock piping from headers back)

I would like to get the correct size to match stock or if It makes more sense to get a bigger pipe to match a typical aftermarket mandrel bend exhust for the future...

Fill me in, what sizes should I tell them?

Bumpasaurus.

I think the stock on a 2gnt is 2.25"
but when you go in just tell them to use the same size pipe as on there.. they'll measure it and all will be well.
But if you want it for aftermarket piping.. 90% (if not more) for the 2gnt is 2.5" piping. As long as it's not designed for a turbo system.

Is it ok to get a 2.5 testpipe with my 2.25 stock piping? I dont want to pay for another testpipe when I do upgrade all of the stock piping.

Will it hurt anything running 2.5 testpipe on a 2.25 stock exhaust?