2010 Liberty Limited Sport Utility 4D engine question

So got this for free. 3.7L has a knock @ 150K. Trans unknown. Haven’t tried to start or do much yet.

I was planning to get a reman 3.7L and drop that in. However, do I have any other options? Someone mentioned a 4.0L would be a better choice but I am a jeep idiot at this point in time. Would that require a trans/ECU change, mounts etc?

I should probably stick to a stock reman and not deal with unforeseen complications but thought I’d ask before I tear into it.

leave it stock; the orignal engine is a good engine if its oil and filter are changed regularly (and NOT at 10k miles)