Building a 3.2L

[Boxy_02]

Hi There!

I am a new owner of a 2002 base Boxster with 103,000 miles, but in great condition.
I am looking at building up a 3.2L Engine to replace the 2.7. The car is an automatic transmission - my question is: Does the donor Engine I am going to start with have to come from original Automatic Car? or does it not matter if it was a Manual transmission car? Are the blocks the same?

Thanks!