A35 is a modified M260 Engine, A45 is M139, a completely different engine with the direction completely reversed ie- turbo on the A45 is against the bulkhead, so no, not a straightforward drop in.

 

M139 is based on an M260,I believe its the same block. Turning it 180 degrees doesn't change much. Just turn it back.

Just like the M133 was based on the M270.

If its the same block, most of the attachment points, might be the same.

Does anyone actually know?

 

M139 may have started life out being based on the M260, but is nothing like it now. Even the engine bay packaging of items such as the Engine ECU is different from an A35 to A45 due to space, the top end is understandably different.

I very much doubt anyone has done this conversion.

 

I was actually considering either M133 or M139, both are forged internals right?

 

Yes

 

Better off rebuilding/strengthening the current engine for higher power.
Not sure the gearbox/driveline will keep up though