Welcome to the forum!
If you have the 6 cylinder engine you may want to have look at UseYourNoggin's exhaust system. It is much better than the original.

 

I do have the best exhaust for the 3.0 litre V6 with stock exhaust manifolds and pre-cats. Headers are best, but not legal. Mine is legal and a bit custom from pre-cats back to main cat. Thanks Tan.
I am not sure about the 2005 exhaust stock design, but if it looks like the 2006, you need to change it like i did.
READ: https://www.mazdaforum.com/forum/maz...-design-28940/

My short ram yet cold air intake is also the best of both worlds as it is short and gets at cold air with a rain deflector for water.

READ: https://www.mazdaforum.com/forum/maz...3-0-ltr-30523/

and: https://www.mazdaforum.com/forum/maz...uestion-32127/

 

Hi Jeff, and welcome.

(from a not so new guy)