[BirdOPrey5]

I'm pretty sure I've heard the global_start hook isn't called on CMS pages anyway. They were going to remove that hook but kept it to keep compatibility with older mods, but didn't add it to the "new" parts of VB4.

I really can't image trying to work on 50,000 pages... good luck with that.

But using the same variable names is a concern. Not only should you avoid the variable names used by vBulletin but also names other people have used in mods you have installed. When I make a mod I'll usually call my variables $bop_post or $bop_thread for example to know I'm not changing data used elsewhere.