BMW 325i after spending $2800.00 at other shop

This BMW's Emission test failed and had a minor misfire. This customer is a long time customer, we have been servicing his car for over 15 years. The story goes like this. We specialize in Japanese cars. The customer had over-heating problem while coming home from outside town.  He had to keep stopping and adding water. He brought to the shop close by and known for specializing in BMWs.  They had fixed the cooling system ($1700), and when he got car back, he noticed the rough engine (misfire), when he brought the car back to them, they replaced the all 6 ignition coils, and some other items ($800). But he still was not happy with the performance. Then they replaced a couple of  Oxygen sensors ($300).  When he brought back the last time, they told him that to fix that problem is a new/used engine is required after researching online for similar conditions/symptoms.
So he left it as it was, no further repairs were done to this problem.
When emission test we performed, and failed. It had 8 multiple codes were in computer memory- Including lean mixture faults and misfire codes on all cylinders. We suspected vacuum leaks so we smoke tested the intake system. We found a leaking port on the intake manifold, cap was missing, and replaced. It was noticed that some smoke had also been coming from underneath the engine cover as well as the intake manifold port.  Due to limited time we could not further investigate the issue and the owner had to rebook to check the rough issue at a later date. When the car returned the owner said the car was noticeably less rough with the manifold port now capped. We tested engine vacuum and found it too low (10 inHg) where normal vacuum should be 17 inHg-20 inHg. We recalled the previous smoke test and this time removed all the engine covers and smoked the intake again. We found smoke coming from the intake and after further inspection found the plastic valve cover had cracks where the two center hold down bolts are. The PCV system on engines will  suck blow-by gas from the crankcase (through the valve cover) and if the valve cover is cracked, the air getting sucked in will causes a low vacuum (at idle). After replacing the cover the rough idle was fixed and no codes have returned since.  Update, the customer wrote us a card and brought a box of cokkies a month later.

This is BMW 325i, production year is 2002, 2.5 L engine,  and it has driven 146,750 km.

This is you tube clip for smoke test;  http://youtu.be/WjEBzXDnth0

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A month later we received a thank you card and a box of cookies.