All depends on the shop, i've taken many people to a local place to get theirs done and therefore I get a good rate. Pipes from heads to H for me would only be like $40 installed. Best choice is to ask around see what they will do for you.
Can't really help on who makes them, but I know they're out there
Edit : Also keep in mind they would need to custom fab for your O2 sensors as well, and or get a tuner to shut off the rears if you only do front.
The stock pipe is preaty much all welded together. Your best bet would be to just buy a cat less H-pipe and save your stock pipe. Here's a site I found that has them for $125 and that includes free shipping and fits stock headers or shorty headers. It also has the o2 bungs for your sensors and you don't need extention harnesses.