I don't know to be honest because the ANY block is unique in being aluminium; it might be compatible. You'd have to use the ANY ECU but that might also give problems; you would have to circumvent any interlocks that normally prevent the engine from starting under some circumstances. Converting the A2 to a full 3L is not possible using Lupo 3L components - there are too many differences. Even the drive shafts are different lengths, not by much though.
RAB
Thanks of the answer! However, my point is not to convert the A2 to a normal A2 3L . Having owned the 3L Lupo for 21 years, I know well the weak points of its technology, and the A2 3L has the same critical components, mainly the automated manual gearbox and its hydraulics. I do not want them. However, the engine itself is good and reliable, therefore I would like to keep the A2 manual gearbox and driveshafts, the ECU etc. and just replace the ATL engine with the ANY engine. Because the main parts to be controlled by the ECU are similar in both engines ( variable vane turbo in both, similar tandem pump, same EGR, same intercooler ) then I would assume that the A2 ECU would see all the same components in the ANY engine, too. Notably, the AMF and ANY would be less identical. Of course, the control parameters would be different for some, like the turbo pressure, but e.g. the fuel supply is regulated by the (smaller) injectors, the ECU just gives the relative control values to them, so that would not be a problem, if the electrical interface is similar. The only absolutely critical point is the mechanical compliance between the ANY engine, clutch, and the A2 existing gearbox. Less critical is the engine attachment: because the ANY engine is smaller and lighter, I would assume it would be easy to do the attachment modifications, if needed.
I know that in Germany it has been popular to convert the 3L A2 and 3L Lupo to manual gearshift, but it looks much more complicated, because then there will be major modifications to the engine ECU, the gearbox control unit, pedals, linkages, etc. I assume the A2 manual gearbox does not have any measured control values to be sent to the engine ECU for stopping the engine like the 3L gearbox controller has, it is just dumb mechanics. When I look the ANY and ATL gearbox pictures, they look very different, but would need dimensional drawings to check if the attachment is possible at all.
Cheers, Jouko