>Changing the re-write flag from last to passthrough makes all the
>difference but does it have performane or security implications? It seems
>to take a little while to process the rewrite on my stand alone system and
>I'm worried that I might bring a production server to a halt using it.

Its almost certain that what you are experiencing as a performance issue is
not Apache mod_rewrite performance but CGI performance. CGI is great for
testing, and perhaps fine for applications that will see very low
utilization, but will put a big load on even a capable server if you expect
your app to get a lot of traffic.

As Jason pointed out you will want to investigate using a facility that
provides for "Long Running Processes" -- check out web-server.txt in the
docs and look for a second entitled just that.

If you have complete control over the production server environment, then
you have lots of choices available to you. If its *nix and Apache, then I'd
suggest trying SCGI since its easy to configure and examples are in the
demo directory.

If you don't have complete control over the production server environment
then you have perhaps a bigger challenge ahead...