I have a 14" magnaflow with a magnaflow y pipe and jba headers, i do not notice anything to bad when the mds kicks on. The magnaflows are very nice, your best bet is to go to youtube and listen to a couple of different set up, see which ones you like and then make your choice
Here is a list of the 3 magnaflows that are currently available for your stock setup and then also the link to the y pipe if interested.
I am going to copy and paste from another thread where I just posted this info yesterday hope none of the moderators mind
Magnaflow does make a very great product on our trucks, and as far as the 4th gen hemis go it is 2.5" in from headers/exhaust manifold to the Ypipe, and then 3" from the y pipe to the muffler, and then 2.5" duals from the mufflers to the tips.
check out the available magnaflow muffler we cary in stock here lowest prices around
Magnaflow 14" Muffler $134.61
Magnaflow 18" Muffler $155.99
Magnaflow 22" Muffler $124.01
These are shipped prices to the lower 48 states.
The only difference in size change is the sound it puts off, maybe very little performance, most of our customers go with the either the 14" it is the loudest of the 3 has a nice deep rich tone to it, and then 2nd most purchased is the 18" it is not quite as loud but still has a nice rumble to it, and then there is the 22" people who purchase this one have said it is louder than stock but still bearable if you will. I think the favorite among most is the 18" it is a nice happy median
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