A recorded installation is cut at every point where nothing visible happens. The soaking of fasteners, the walk to find a different socket, the wait for a second pair of hands, the re-hanging of a section that went up the wrong side of a heat shield: all of it is gone. What remains is the part where bolts turn easily.
Budget the job by counting joints rather than by watching the clock in the video. Each joint has a release, a clean, an alignment and a tighten, and each of those can go wrong independently. A system with many joints is not proportionally slower, it is slower in a way that compounds.
On an older car, most of the elapsed time goes into fasteners that no longer want to move. Nuts corrode onto studs, studs corrode into flanges, and heat cycles bind the two together in a way that no penetrating fluid reverses quickly. Plan the day around the worst fastener, not the average one.
Start soaking the day before if you can, and work on the rear of the system first while your patience is intact. The joints nearest the engine are usually the most heat-affected and the most difficult, and reaching them with a clear head matters more than reaching them early in the day.
Anything made to a drawing is made to a nominal size, and the car is not nominal. Hanger positions, flange angles and clearance to the body vary between cars of the same model, and a section that fits one will sometimes need to be persuaded onto another. That persuasion is what takes the time.
Where a part is being made for your car rather than chosen from a shelf, the first fit is a check, not a finish. Treat the first assembly as a trial: hang it loose, look at every clearance, then take it down and adjust before the final tighten. Read how the custom work route handles that trial stage.
Measuring on the car is slower than measuring on a bench, and it is the only measurement that counts. A pipe cut to a bench length will be short or long by whatever the joint overlap turns out to be, and that overlap is set by how far the section can slide on its hangers.
Measure with the system under its own weight and supported as it will be in service. A section measured while a jack is holding it up will be wrong by the amount the system settles when the jack comes back down and the hangers take the load.
The job is not finished when the last clamp is tight. Old gaskets, swarf from cutting and the marks left by a slipped spanner all have to be dealt with, and on a replacement exhaust section the inside of the tube matters as much as the outside. Loose material inside a pipe finds its way to the muffler.
Wipe joints before assembly, check that no offcut has been left in a tube, and run a rag through any section you have cut. Debris that reaches a baffle will rattle for the life of the part, and the rattle will be blamed on the part rather than on the installation.
Give the job a finish time you can extend without consequence, and a way to leave the car immobile overnight if it comes to that. A car on stands inside a garage is an inconvenience; a car on stands in a shared car park is a problem that forces bad decisions.
Keep the old section intact until the new one is proven. The old part is your reference for length, hanger position and joint style, and it is worth more on the floor beside you than in a skip until the system has been driven and checked.
