I am moving on on this topic. I found a place in Warsaw that seemed to know what they are talking about as far as FIPs are concerned. I took a risk and asked them to check and adjust fuel dosing for each cylinder.
They did and I found out the span I had was 20-25% between the cylinders. As I spotted by difference in colours of the spark plugs, different CO in left and right exhaust pipes, etc. The car was telling me what was wrong with her...
I am enclosing the results and spark plugs picture for comparison.
I will fit the FIP to car this weekend, see how it works.
