Wow. This is alot more discussion than I thought this would inspire.
A few facts: I've done 100% of my own work since the late 70's when I was handed down a 73' Volvo 164. I've rebuilt engines and transmissions and done all the sundry wrenching that comes with liking and owning interesting vehicles. I built all my road race motorcycles and sprint karts, and never had a mechancal DNF.
By profession I'm a Senior Product Designer for good-sized solar energy service company, and have worked around the R&D - prototype - making stuff world for a while. In prior lives I worked in the powersports industry in the parts-service-sales side, and before that I toiled as a bicycle mechanic then service manager then manager of the shop side of a chain of shops. I was known for excellent work and a depp commitment to customer service.
On a regular basis I make parts to prints from sheet metal, bar stock, plastics and composites. I have a lathe, mill, shear, brake, presses, saws, TIG, MIG, gas and plasma at home and at work. To answer whoever implied that I didn't work on my stuff by way of asking what systems I'd worked on the past 6 months: I had the suspension on and off the M3 so many times last spring and early season getting the car dialed that once it was working I dodn't need or care to work on it any more.
The parts in question were all top-shelf stuff; Zionsville full race cooling system w/ a Stewart water pump and all new hoses and wiring kits. New OEM Lemforder front control arms, SPC rear adjustables, Powerflex bushings for front LCAs and upper 4 subframe bushings. Aluminum flywheel and Clutchmasters stg 1 clutch pack. Redline fluids, water wetter, etc. All stuff that fits...
I did mention that I'd bought all the OEM parts as I'd truly intended to complete the work myself and the owner said "that's no problem at all; who's got time anymore?".
It's clear that the work was broken down into many flat rate jobs, many of which included work that was in multiple other jobs.
Example? The car was on a lift with the wheels off. I'd asked for my race pads to be swapped in. I was charged 2.4 hours labor. $238.
I can do this including a wheel swap in the pits at the track in a 1/2 hour using an 18V impact, a floor jack, a 7mm allen key, a flat blade screwdriver and a C-clamp.
I've worked on "stuff" for a living for many years. Bicycles, motorcycles, cars, lab robots, whatever. I'm cognizant of the need to earn a living. If the work was executed remotely as well as I can do it myself, I'd have said $5100 was very expensive but at least the car was done.
It's the fact that I was charged 4 times to R&R the exhaust and driveshaft; that I needed to completely redo the fan wiring; that I needed to replace the broken fusebox. BTW, someone asserted that the hours charged were justified due to several mechanics potentially working at once. Nope. It's flat rate. Job charges X labor, shop does the job how ever they want to maximize profit.
I was charged $100/hr for every hour the shop was open from 8-5 Tuesday-Friday, and the work wasn't stellar.
Just facts.