[kmike]

Originally Posted by orban

Search posts and display as threads:

Let's say somebody searches for "book" and returns 150.000 posts. Those 150.000 posts are in 40.000 threads. If you find any way to fetch all 150.000 threadids, sort them and make a unique list of them, then let me know, but I really have no idea how to do that. I also think that this is a major problem of the vB search...(there are queries with several tens of thousands threadids in them).

I assume you're storing threadid as a group attribute, to support searching within threads. So you'll get it back in the search results for every post found.
Just collect all threadid's in an array, throw out the duplicates using array_unique, and voila, you have your results as threads.

Originally Posted by orban

Search threads and display as posts

There's no such option, looks like you mean "search titles only". But posts have titles too, you know?