Date registered: Dec 2005
Vehicle: 222.132 & 221.122 & 212.025 & 906.633
Mentioned: 3 Post(s)
Quoted: 32 Post(s)
What made the pistons fail?
Your first post had a typo, there is no 642.640 engine. The 642.940 and 642.950 must be mostly the same engine. I'd suggest you to browse EPC for the two and compare which pars actually are different (I doubt anyone is willing to have that effort on behalf of you, someone might know the difference by heart though and could help).
I guess your intention is to take the ECU from the old engine to keep it matching with the rest of the drive authorisation parts? You should code it for the new parts though (injector classification etc.).