Would it be crazy loud if I just ran straight pipes out the back from the headers?

In my opinion straight pipes generally sound like ****. Don't know why. They just do. It gives it that "cowboy rap". That's what we call it around here. All the chevys with duals have that sound. The hollow, fake performance sound. Just sounds like garbage.

You can run mufflers and still hear the exhaust. The exhaust and note primarily comes from the engine itself. If you're running a dog engine. You have to over compensate by running a shitty exhaust to make it sound "good". But if you have a good built engine, then almost no matter what exhaust you put on there, you'll hear it. I recently changed the exhaust on my 340 to the following:

Hooker headers - Full length 1-5/8 primarys, 3 inch collector, 3" exhaust with H pipe into dynomax bullets, dumped right after the mufflers. Just before the axle.

It is the definition of loud. My buddies hear me coming over from a couple blocks away. It's basically one step down from open headers. Sitting at the light everyone stares. You hear AND feel the lope of the cam. At idle it booms. At full throttle it screams. It will hurt your ears. And if you have any conscience what so ever, you will feel bad every time you fire it up in the middle of the night leaving a friends place or something. So be ready for that.

I will try and upload an open headers and exhaust video later.