I just felt like adding, it is best to use Bosch 150 style injectors if you want a direct fitment and no washers.
All Bosch injector part numbers start with a "0 280 XXX XXX". The first three X's are the injector style. Bosch has two commonly used styles, the 150 injector which is wider, and the slightly newer 155 style which is narrower. So a 150 style injector will have a part number like "0 280 150 947".
When it comes to the two injector styles, practically no dimensions are the same, other than the same O-rings. In some cars the 155 style don't work at all. I recently helped out with an efi conversion on a 1989 Mercedes 190E, and where the 150's were able be used, the 155's were a lot shorter and wouldn't have worked well.
As an additional note, most car manufacturers run slightly undersized injectors since smaller injectors provide more accurate fuel metering and better fuel economy. BUT in the case of the M42, these are perfectly sized(20.35lbs/hr) for the engine and should be able to support 138 hp with 43.5 psi/3 bar fuel pressure (BMW regulators run at 3 bar + or - 0.06). So if anyone is claiming their car is running either lean or rich, then likely they have a mechanical problem or less likely BMW didn't make a very good fuel table.
