in my state the exhaust has to exit from under the vehicle, that may be what people are talking about. If that is the case just have them mount everything before the axle. then when you get home you can hack the ends and throw some turn downs on.
I had an exhaust bent up a my local Meineke. It was on a car, but I was very happy with it. They did exactly what I asked for.
My blazer has duals from a local place called Red Run that only does exhaust. I am not happy with it. I had them exit right next to the hitch. when they backed it out of the shop the tips were exactly the same distance from the bumper, BUT one was level and the other was pointed slightly down. They had 2 guys working on it. each guy did one side.
Bad idea. basically one side came down over the axle and turned a 90* and ran straight out the back. the other side kind of sloped towards the back.
I asked them to rebend it. they put it on the lift and went after the tube with a torch and a broomstick. WTF! now the sloped side runs level but it exits 2" higher then the side that was straight to begin with. At this point I am amazed that they can be this dumb. I went there on the recommendation of my friend who sends all the jeeps he works on there. Duh! Heeps have single exhaust, it doesn't have to match anything.
Eventually they got it close enough and I got tired of not being able to step in and fix it the way I wanted.
They sell dual exhaust kits through summit or jegs or your local speed shop. about $100 for the pipe, you provide the mufflers and cats. I have that kit on my woods truck, it dumps right over the axle. You might want to check that out.