Advice on engine swap.

Hi everyone, got my mr2 last month and its got 200000km on it.
The engine seems fine but i was thinking of doing a swap soon as its pinging alot and it seems like its had a hard life and a few more issues.
I did my research and found alot of people putting 1-mz into them just wanted some advice on how big of a job this would be and what other options I have. Another thing and the biggest thing is the time id be spending on this project. I really don't want to be without a car for weeks and weeks.
 
thanks guys.