Are 2.5 2006 Engine Blocks all the same

Can you provide the website that you have? There are some differences from short block to long block to a full on trouble free swap. You might honestly just search for it on any of the real forums as it's been a few years since I've done the research. I know 98 foresters had DOHC and then 99-04 iirc are def compatible for at least short block (some had some cyl head differences, especially for spark plug position). After that, i.e. 05+ I really don't know. It is just info I never needed to know, we have an 03 and 04. I would almost guarantee that info you need is on at least one of the subaru forums, SF, nasioc, etc. I hope that helps or at least eliminates some info (98-04).