1997 M3 sedan engine overhaul

[Matt97m3]

I have a 97 arctic silver M3 sedan that has stopped working last year to the date. Basically I was driving to work and on lunch that day I accelerated, noticing something different in response I gave more gas and to my surprise it accelerated very slowly.....318ti slowly (lol jk). Then progressively the M3 started to decelerate. Took it home and shut it off to check codes and see what was up. Computer says "major vacuum leak in cylinder 5 and 6" take out the stethoscopes to listen around the block heard no knocking or abnormal noises and no hissing, replaced the spark plugs and put fuel cleaner through the system and no luck. So I took it to a guy who said he knew what he was doing and paid him to look at it. Long story short he was under qualified and had no idea what he was doing, took my head off and basically let it sit there for ten months. I'm fed up. I took my M3 back and it is at a highly rated BMW repair shop. So far they have tried to do a 100 dollar diagnostics but it is something in cylinder 1 and 2, so the head needs to come off, again, I said ok that's fine another 500 dollars and instill don't know what's wrong, they have taken the head off and my head is severely pitted and corroded from heat and coolant so they are repairing the head at another 150 dollars so they can do a compression test on Friday......... I miss my M3.
Anyone have any ideas as to what this may be?!?!?!?!???????!?!??

[Rudolph320i]

heat and coolant in the combustion chamber? sounds like the headgasket went and possibly burned lean too.

[Matt97m3]

heat and coolant in the combustion chamber? sounds like the headgasket went and possibly burned lean too.

Hopefully there is no major damage to the cylinder walls if that's the case. Might be time to find a 97 euro m3 motor?? Haha

[fun2drive]

Couple of questions.
If the head is pitted how much did they deck it down to?
They need to run a thicker head gasket if they plane it down more than 0.010".
Also the head needs to be polished to a roughness average or arithmetic roughness (RA) whichever term you prefer of 50 or lower. BMW specs 20 or less but most accepted rebuilders use 50 or less.

Why your head is pitted is pure speculation but a warped head would allow the headgasket to leak or if it overheated and was unknown to you it can blow a headgasket. Anyway you cut as long as your cylinders are OK and pistons too you should be fine. Expect to see some scoring on the cams too which is all normal wear and tear...