Welcome the MKZ Forum, Scott. Congratulations on your MKZ. I had a 2012 Sport. While the 1st-gen cars weren't available with a lot of the advanced features of the 2013+ cars, they still have a lot going for them.
Search around here and on the Ford Fusion Forum for what others have done WRT exhaust. Just realize that it's never going to sound like a GM LS V8.
Edit: bbf2530 got in just before me.
Hi Scott. Welcome to the Lincoln MKZ Forum and congratulations on your new MKZ!
Just so your expectations are not too high...No matter what muffler we put on, we can not get V-8 sound from a V-6.
If you do a forum search, you can find many existing threads on aftermarket mufflers for our cars. Generally speaking, the three top choices for mufflers are Borla, Magnaflow and Flowmaster.
A brief recap: Borla is the highest quality and highest priced (you get what you pay for). More grumble than stock. Not obnoxiously loud. Very high quality, and price.
Magnaflow is the second choice quality wise and priced lower. Louder. Some complain of a cruising speed drone.
Flowmaster is the least expensive, but many complain of an obnoxious/headache inducing, cruising speed drone, and wind up reinstalling the factory mufflers.
You can go to the company websites for those three companies and see what your choices are.
Keep in mind that no aftermarket muffler or cat-back exhaust will increase horsepower, torque or mpg's. No matter what their advertising shtick may state.
Let us know who you make out and good luck.
I just purchased a new-to-me 2012 MKZ with the 3.5 and I'm really diggin' it! ...all except for the vacuum cleaner-like sound of the exhaust. I was wondering if anyone had any experience with performance mufflers for these cars. Something definitely not loud, but with a bit of grumble, sort if what a stock Suburban sounds like with its LS motor. Thanks in advance!