Extremely loud cabin noise

Picked up my 2005 Grand Prix GXP and was in love at first sight.
On the hour and a half drive home I had a bashing headache from how loud the interior of the car is.
I thought it was just the car having a big V8 but the more I looked into it the more people were saying how they loved how quiet the cabin was.

Mines not quiet.
at all.

Does anyone know what could cause all the noise?
Poorly sealed car?
Leaking exhaust?

It could be exhaust. It could be tire noise. It could even be a wheel bearing.

Maybe get someone who is more adept to cars to go for a ride to help you narrow down the noise.

also i video would really help out here.

Look under the car and see if it looks like a replacement muffler has been installed. A lot of the popular mufflers create interior "drone" since they are just empty metal boxes. If the muffler is new and shiny or has fancy words on it, go see a muffler shop for options.