Automatic ads

Currently I use mod_ext_filter to insert automatic ads via a perl file used as output_filter. I have 2 big problems: 1. Sometimes (on loops), buffer becomes huge and cause apache/server overload. I need a way to limit the buffer to let say, 10-20M. 2. My actual filter prevent scripts like vB, IPB, Nuke etc. (php+mysql) to work correctly. It is only displayed the ad code, sometimes nothing. This error is only related to IE as Mozilla and Opera working without problem.