I have a 2006 Charger 3.5 Liter (i know, I know - but at least I keep it clean). I wanted to add the dual exhaust from a 5.7 liter R/T. Will I have to make any modifications?

 

I don't believe I've welcomed you so WELCOME to the forum!

Yes, you havethe following stock: exhaust manifolds to cats to midpipes that go into a Y. From the Y it's a single pipe to the tailpipe.

You will have to get rid of the Y (go w/a H or X pipe which is optional) then out to the rear tailpipes w/dual pipes.

This thread has info on third party exhausts for your car. Zoomers has a true dual Catback with your name on it
https://dodgeforum.com/m_548643/tm.htm

 

the mopar accessory catback exhaust comes available in single or dual for the 3.5. i have seen a car with the duals and it sounded real nice. it's worth looking into

 

i just put an exhuast from an SRT8 on my 3.5, all the guys had to do was make an adaptor that went from the stock 2¼" pipe to the 3' SRT8 exhaust, and then i bought the hangers from the dealership and just bolted those right on! , looks nice, gave me a lil sound and a better look, not sure about the performance, but I got a smokin deal on the exhaust so i couldn't pass it up!