Not knowing what's under the hood, some things to consider if not yet implemented:

making the search AND, I've actually found it quite frustrating that it is OR. Or allow logic, I am not sure how this affects search time, but it should result in a smaller recordset to handle, and a smaller page to return.

forbid searching for perl keywords (operators, functions...) that are not ANDed with something, shortcircuit to Simple Search.

likewise rule out badwords (common words), at least not when ANDed with something else.

paginating the results. Bandwidth in bursts, and and a good database with LIMIT ought to stop once it reaches the limit. I imagine subsequent pages would need to be told the node ID whence to search, to contintue with the performance boost?

--
perl -pe "s/\b;([mnst])/'\1/mg"