I've been in your shoes before. I hate the name brand shops, and yet I find myself using them from time to time. Mostly my wife's vehicle, my R/T a few times, but never my SRT.
They all seem like a scam. Meineke tried to charge me like $28 for an air filter in my wife's vehicle once, and it was $12 at AutoZone.
The reason I find myself using them is time. My wife works full time and we have a 2 year old. The guy's who do the best are a small local shop, but they take forever to do anything. An oil change is a drop off all day event. The dealer takes an hour and a half, and Meineke takes 20 minutes.
I don't think either the dealer or national chains have anybody with a clue on their payroll, but usually the dealer will guarantee their work.
If money is tight, just go to Midas or Pep Boys. Just look over it and listen for a few days to see if anything seems loose or rattling. If anything isn't right they'll fix it. Putting a cat-back on isn't rocket science, a lot of it has to do with most people not having the necessary equipment to do it themselves.
As much as I hate Meineke, I've never had anything done incorrectly.