Queries of all the type of forum softwares

As Smartys indicated, several simple queries could be faster than one complex query. Certainly queries should be as efficient as possible but simply looking at the number of queries won't tell you much.

In fact there is more to it than page generation time, I think it really comes down to "perceived" page generation time. Looking at AEF's topic page it seems slower than it actually is because of the table based layout and a lot of graphics.

That depends on the quality of the modifications.

The question doesn't really make sense since SMF, VB and phpBB have different feature sets. If I wanted a forum with an identical feature set as VB then I would buy a VB license. I can't see any point in modding one forum to be a clone of another.

The idea of starting with a forum without all the bells and whistles is to add only the extra features that you want and end up with something that exactly fits your requirements. If you actaully want all the bells and whistles it makes far more sense to select a script that already has them.

No way of telling without actually trying it but in theory I would have thought built in features ought to be faster because the code was originally written to accommodate those features.