The custom exhaust is basically the same thing man they will run it exactly how you want it done either dual pipe ran or single basically any choice you want along with what size pipe you wanna run along with tips or no tips. If you do this you will save money and your truck will perform just the same to be completly honest lol you might just get a sticker that say's gibson or something ha. I would do this since they don't make one's for your truck and do research about what size pipe you wanna run and either dual or single exhaust. If you want too get online and buy tip's from gibson,corsa,magnaflow or whom ever along with a muffler if you want one and save money from not buying at a local shop and can find allot more stuff you want online compared to exhaust shop. I bought my Flowmaster super 40 series dual in/dual out offline and save about $25 bucks and along with 3 1/2 by 18 inch Painted gloss black rolled edge tips and you can't get these at a shop. I also have a magnaflow x pipe will be here tom. i bought offline and will even out the exhaust flow and give me a lil bit more HP and Torque and paid $80 bucks for it and to help it i bought a K&N air filter. Basically what i'm sayin this is your last option and you can get whatver size pipe you want ran that you want from offline that want fit and just buy whatever else separate so it will be a perfect fit!
