Advice needed : Faulty ECU

Hey guys,



Here's the background story of my car:

For the most part of 2014 my car has been very sluggish in the bottom end but noticeably faster in the top. i thought this was due to changing headers.



I was away for 2 months during Christmas and when i came back every time I started up the car and drove for a couple of minutes my 5th cylinder would drop out. Took it to mechanic and replaced coil packs/ spark plugs etc still the same. My mechanic told me it has to be a electrical problem.



So i took my car to an auto electrician and they sent my ECU away to be tested. Test result came back that it was faulty. Apparently something is causing my ECU to be faulty thus causing my 5th cylinder to drop out after cruising for a few minutes.



The guy told me that it'll cost me 2k for a new ECU but he is trying to find someone that could 'maybe' clone it so it would be much cheaper than buying a new one. They also do not know what could be causing the ECU to be faulty.



So has anyone had a similar experience?

And are there any cheaper alternatives apart from purchasing a new ECU?



thanks in advance



Only things i've done my car (330ci manual) is;

Full exhaust (including headers)

Changed VANOS seals (maybe this had an effect? i dont know)

suspension