Exhaust system advice and shop recommendation

I removed the Mopar P5249971 headers from my rig, for obvious reasons. I'd like to replace it with the same thing so that it will bolt right up to the existing pipe, but that's not likely to happen because Mopar doesn't make the P5249971 anymore, and I can't find one. (Actually, I did find a seller on line that seems to have 'em, but the price is beyond ridiculous.) So I'm going to have to go another route.

My question is, if I install another header and need the exhaust pipe modified to fit the replacement, is that something any muffler shop can do? Or would it take special skill? If it takes any special skill, what shop in So. Cal. would be able to do it? (Preferably in the L.A. Area.) Any recommendations would be appreciated.

Sport Muffler in Santa Monica on Lincoln is pretty good. I've used them several times and been happy with the results. The owner's name is Mario.

Cool. That's pretty close. Which is good since I'll have to have the rig towed there. Thanks, Scott.