Any suggestions on a good combination of Intake, Headers, and cat-back system to get the best sound. 100% bolt-on preferred!

 

GT mufflers are good.

https://themustangsource.com/f801/20...r-30-a-482074/

 

Glad to here you are "stuck" with the 4.0 too.
I have looked into the true dual exhaust system and can tell you that the rear valance can be bought for around $50-$100 off of craigslist. The roush or boss version for $175
The pypes systems you can get from American muscle for around $475. The ford racing version (power pack) for $850. OR $1200 for Cervinis p/n 8048 2010 Side Exhaust with Skirts & Rear Valance.
Headers can be found for around $500. I have never looked for an intake, and don't think one could be found, maybe if you look at the 05-09 V6's or Ranger.

 

stuck? it's not a 3.8... anyway true dual won't do much on a 4L unless you're adding a blower, the 2.5" is more than enough to empty the exhaust, any after market or GT muffler will do, or a Mac reverse Y if you want a dual.
Get a tune. also an aluminum driveshaft makes a big difference.

 

Put a X-Charger on it, only way to make any real power on the 4.0, forced induction.

 

Just added stock 2010 gt mufflers with an X pipe to my wifes 2010 4.0 V6 Mustang. Also installed the GT rear valance. It not only looks great, it sounds amazing. What a difference from the stock single exhaust. The car now even runs better, the auto shifts smoother, and feels a little peppier. And because the mufflers are Ford there is now drone whatsoever. Absolutely no disappointments.

 

If you can find a set of GT Take Offs for the exhaust I think they sound good on a my V6 with the Pypes X-Pipe and left GT over the axle pipe. That is what is on mine.
American Muscle also has a 2010 intake and tuner combo for our cars now.
For the headers, unless you are going long tubes don't bother because the V6 cast iron header is pretty good for a stock Ford item.
Rear Valance I bought the GT500, $122 from Ford when I went duals.
BTW, the being Stuck with the 4.0 is not a bad thing, mine has beat up on a few GT's and a couple of 2011 and up V6's in the twisties, I know better than run them in a straight line

 

I meant it sarcastically, since we have the "old" motor- with less hp and mpg. The new motor you can get a plethora of parts for and has people excited about Don't get me wrong I love the car, but got kinda feel screwed since I bought the new model and the next year the motor was out-dated.