I HATE exhaust depot. I went there to have them make a section of mid pipe for my other car and they charged me $150 and took 3+ hours. The joining piece was 6in long and had one flange with a slight angle. Complete waste of time, I could have made that on my own mig welder....to hell with them.
On the otherhand, Miami Muffler (VRS) is flat out awesome. They made the first set of turbo pipe for my v6 MX6 a few years back and I've run several exhaust bulk buys through them. They are down by SW184th and a few blocks of US1. So, pretty far south Miami.
The guy you want to speak to is Miguel Jr., he pretty much runs the entire place now, but doesn't work on Fri. Tell him Jordan with the Green turbo MX6 sent ya, and he'll help you out.
Don't count on too many shops to make a downpipe for us, but I'd bet they would install it for you. Miami Muffler does have a CNC Plasma Cutter to make flanges and what not though....
I would just buy a downpipe, as that will probably be cheaper in the end.