I wouldn't classify this as a bug, just more of an oversight. The max_matches variable in the sphinx.conf file is ignored when using the PHP API script. It doesn't matter if it's left at the default 1000, the 1500 that orban's file has been modified to use, or 1000000 as the config file says not to do. If you want to change the number of results returned then you need to change line 15 of 'includes/sphinx.php'.
Old:
PHP Code:
$cl->SetLimits ( 0, $vbulletin->options['maxresults'] );
New (replace '2500' with the number you want):
PHP Code:
$cl->SetLimits ( 0, $vbulletin->options['maxresults'], 2500 );
Otherwise, great work! This has really sped up searching on the forums I have used for testing (6K posts, 820K posts, and 3.2M posts).