Classes versus native functions

Hi, I was wondering if anyone knew (and could quantify) the performance difference between a script that uses PHP's native XML functions - for example, DOM functions to add/remove nodes - and one that simulates these functions via a class - like the PHP.XPath class. I would assume that simulating it via a class would obviously be slower than the native function - right? But are there any numbers to back this up? Any ideas on how to build a test case to check this? Thanks in advance! Please CC my address above as well as the list if you have a response. Vikram -- Friends help you move. Real friends help you move bodies.