Hmm...don't have much experience with exports.
Just to reiterate, the entire dataset is being exported, even though in the report some of the records are filtered out, and of course we don't want to see these records in the CSV.
This is tough, the only thought that I have is to use a stored procedure for the report's datasource. This way, only the records that you want ever make it to the report...there aren't any extra unwanted records for Crystal to export.
this is probably a big change and won't be quick and easy to do, but it can be done.
Perhaps someone else has more experience with exports can give a more helpful answer.