I'm aware that having more, or particular, options added to a new car delays the build time, but what's the reason behind this? I'd always assumed they just go along the production line and either have or not have bits added at every stage. Or are there separate parts of the line that only work on certain days of the week?!

Also, I only just noticed today after having my car for 10 months that the rear centre seat has no holes for a headrest (not that I want one). Does this mean if you add the restraint as an option you end with a different seat, ie one with holes in?

Standard spec cars can be built without the actual need for a customer to buy it - like shelf stock. If someone wants a standard spec then often it's supplied from a ongoing stock line, as opposed to waiting for them being built from scratch.

Factory options means they can build shelf stock and they have to be added during the factory build - thus meaning you have to wait for the car to actually be built.

Factory's dont normally produce Standard stock unless they have an order. However Dealers will order standard spec cars in groups to cater for demand. So the wait time is often less. A car with options has to be sent to the factory, built, and shipped to you.

There isnt any factory that preduces cars without orders, if they did it wouldnt be a very " Just in Time " Strategy for parts.

Also, optional parts can be on back order due to demand. If they can build 10,000 cars in a specific time, they'll know they'll need 10,000 engines, 10,000 windscreens etc etc as they need these on every car. It's hard to judge how many of the optional extras they need, as it's customer specific, therefore if they are out of stock and short, then that can delay the build.

Ahh, but they do build others just for stock, as mine was White ZetecS with city pack, street pack, leather pack and blue dash/door cards, and it was just sat in stock in the compound, my dealer found it, and got it imported!