TheAsdfDude

Hello all! Frequent visitor, first post. Hope this is the right section! Feel free to move it if its not.

My car:
2006 Civic EX AT
1.8L SOHC I4

I recently started leaking coolant on my car, took it to a shop and they said (and showed me) a crack in the back of the engine block, which was the culprit. This is perfect, because I was looking into swapping engines anyway already. I realize I could just swap out the block, but that's no fun, now is it?

So, I'm faced with a few options. Keep the same engine type, which I believe is the R18. Correct me if i'm wrong Or, I could upgrade to a little bigger engine, such as the K20 series, specifically the K20Z2 or Z3.

I'm wondering if this is even possible, and if there would be a problem with the compatibility of the transmission, considering that the K20 is most likely for manual and my car is automatic. Also, there is an increase in bhp from 140ish to 200ish, which could also be a problem. This is my first car, and first attempt at a project, other than standard maintenance. So, please, no hate if this was a stupid question. Thanks!