X-pipe and muffler took me around 2 hours. Did it all myself, and with the car on jacks. I've done the mufflers so many times though you'd think I was trying to take Crfine's record muffler on/off record from him (nah, I'm really not that close, he's still way ahead).
If the car were on a lift, and you have an impact wrench (which a shop would have), I'd knock around an hour off that. (Shop that did my E92 mufflers only, before I started DIY'ing, did that job in 30 minutes. Lift, impact wrench.) I'd estimate about 1 hours of labor for a shop doing the work, maybe 1.5, can't see it being more than that. Could be wrong, but that's my best shot.