if HG went and it overheated, get the head skimmed or a replacement 2.0 head. 2.2 is DBW, so would cause a few issues
Sorry mate but your wrong, the engine WILL go in and work if the original none DBW 2.0 inlet manifold etc are used.
Where did i say it won't go in? :-/ Just said it would cause issues. 
I suggest getting the 2.0 head skimmed and put back on, as you know the engine
You state that it would "cause issues" but don't say what issues, therefore you obviously aren't too sure what your talking about.
A 2.2 lump WILL go in without causing "issues" as most of the components that would need to be changed over would be taken off to remove the engine any way!! 
Also, you said that he will need to "get the head skimmed or a replacement 2.0 head".
I know for a fact that a 2.2 head will fit a 2.0 because it is EXACTLY the same head and I have fitted one to my 2.0 engine. In fact the head in facelift cars has 2.2 and 2.0 cast into it. 
Jamieo,
sometimes the style you use is more important than actually what you say..
Here, everyday many help threads are open, if everyone keeps their knowledge with the fear of saying something wrong or incomplete , maybe most help requests will remain unanswered..
And remember this is not a site that you pay money..
All members trying to help each other with good intention which can not be criticised. its upto you to accept the answers or not..
Knowledge is what people are after, not people guessing. Telling people that doing something may cause "Issues" without pointing out what the said issues are just isn't helping them at all.
And, as it has been pointed out by a reputable forum member, the base 2.2 engine
IS a direct replacement for the 2.0 engine.
I don't know why you have jumped into this thread at this point but I suspect your possibly one of Tunnies mates trying to stick up for him, or at least that is how it looks to me, but , hey at least you have bumped your post count up by 1.
Over the years I have been a member of lots of different forums and it irritates me when people come onto threads and offer sketchy duff "advice" without properly reading what people said in their posts, it isn't helpful at all.
All the guy who originally posted the question wanted to know was would the 2.2 engine fit into his car and onto his gearbox, he was told by a mechanic that his engine "was on it's way out due to being baked".
A few posts down Tunnie said " I suggest getting the 2.0 head skimmed and put back on, as you know the engine" If he had read the post properly he would see that a mechanic had already condemned the engine and that "Spin" had already had the head gasket done and the head skimmed.
So, bearing all this in mind, are you saying Tunnie's style at answering posts where people are asking for advice makes up for his lack of reading the reading the posts properly?