Hey guys, bought a '14 ST about 3 weeks ago and couldn't stand the lack of noise. The ST is a single 3" exhaust so you all know. All I did was buy a Thrush straight through design glass pack, two flared pieces of 3" tubing, 4 clamps and one hanger. Took out the stock suitcase of a muffler and pieced together the tubing and Thrush and voila, beautiful V8 sounds!! Can't be happier with it and it cost me about $100 and 3 hours of time. Took my buddy for a spin today and he was super impressed with the sound (and the power!) but he does drive a Ford. Will try and get picks tomorrow and post them.
Sounds like an awesome deal.. I've been thinking of doing the same thing with my 09 that I just picked up.. At least as a temp plan, will look into doing something more permanent at a later date... I look forward to seeing how you did your setup, to see what I might be able to work with on mine..