I'm still working on the regex, I'm not sure what's wrong with it yet... It seems like something isn't parsing on it, but so far what I have is:
$post_body = preg_replace('/<div class="ubbcode-block"><div class="ubbcode-header">Warning, Spoiler: <input type="button" value="Show" (.*?) \/><\/div><div class="ubbcode-body"><div style="display: none;">(.*?)<\/div><\/div><\/div>/si', '', $post_body);
It'll at least retard the viewing of the spoiler, well, the post in general... I'll try to get it working as soon as i can figure out what i'm b0gging lol