I assume we're talking B21F with K-Jet injection. The other posts gave you good advice. Look for the simple things first when it won't start. Do the fuel pumps run? Do you have spark? A simple fuel pressure test will tell you a lot. The K-jet system maintains a standing pressure in the fuel system when the engine is not running. This standing pressure is not great enough to open the main injectors (one at each cylinder), rather it allows the cold start injector (mounted in intake manifold) to immediately inject fuel when it (electrically) opens and also allows the pump to quickly build enough pressure to open the main injectors when you crank the engine. This allows for a quick start when the engine is warm and the cold start injector is (by design) inactive. The spring opposed fuel accumulator (mounted by the main fuel pump) accomplishes this and keeps pressure on the system after the engine is shut off. If you have a leaky fuel or cold start injector, it will let this pressure leak down and cause a hard cold start or restart when the engine is warm. Remember, the K-jet requires pressure to open the main injectors as they are mechanical and are held closed by a spring inside each injector. They remain open all the time while the engine is running (pressurized). If this pressure is not available (as in leaky system), the pump will have to run for a few seconds to build system pressure before the engine gets enough fuel to start. This is done while you are holding the key to start and draining the battery. When the engine is cold, the solenoid operated cold start injector opens (if it's operating correctly) as soon as you turn the key. Again, if the standing pressure has leaked down, it will take longer to start as it builds pressure.
Don't throw money at the problem until you know for sure what's happening.
hope this helps
steve

It probably is the fuel pressure regulator but you can help it start by cleaning off the contacts on the cap and rotor. I recently had a no start condition because of this. It's so easy it is worth a try.
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Simon 80 240 307k 18 years. 'White Lightning'

Yhis car has continuous injection I assume. The part is the warm up regulator which adjusts the fuel pressure in the fule distributor. This part is the last one you want to replace after all else has been eliminated. As you have seen it is very expensive, and they very seldom fail.
I would guess also that if you have a no start, then it is unlikely this is the problem. The regulator acts as a choke would on carburated cars, it richens the mixture when the engine is cold.
Unless it is awfully cold where you are, the car would start with a faulty regulator, just would run badly until warmed up.
Also the warm up regulator is easily tested with a fuel pressure gauge. You do have to first get the car to start, but then by simply seeing if the regulator changes the pressure you can determine whether it is working correctly.
With a condition as this you must get to the basics. Do you have spark?
Do you have compression? Do you have fuel flow and pressure?
YOur car may have a cold start injector, a fuel injector just below the trottle body which injects fuel when cranking the engine. Check that this is working, a much more likely culprit and a lot cheaper than the WUR.
If your mechanic is unfamiliar or unwilling to do a fuel pressure test, find a new mechanic.
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744 & 745 16v 4+OD, 245 SE auto, 242Ti 4+OD, 245DL auto parts car