not allowed

Apologies mods, should have posted in the " new members" section, if you could re-locate for me it would be appreciated 🙂

Hi all, my son is looking to buy an Imprezza, and it falls to me to avoid a lemon ! He is looking at around 2007 2.5L manual models. To that end, I have a few questions I hope you all can help me with: 1. Other than head gaskets, and usual used car things, any specific problem areas I should look out for ? 2. Speaking of head gaskets, how does one check these on a flat four, as presumably they are hard to get a look at ? 3. Presumably the difference between STi and standard is either a bigger turbo and/or higher boost levels, would this make a non STi less likely to have head gasket failures ? 4. Any other advice you feel relevant ? Thank you :)