Companies are not allowed to respond with offers in this forum. You might get a better response if you make a request in the "Web Hosting Requests" forum towards the bottom of the page at webhostingtalk.com
Also, vBulletin has the ability to compress the content aside from what is being done with mod_gzip. Therefore, I am not sure it would be a good idea to compress something that is already compressed. However, for you php site. This makes sense.
You can either do gzip compression through PHP's ob_gzhandler or through mod_gzip. The latter has been said to be the more efficient way. If your whole site is PHP, you could do with a host that doesn't have mod_gzip if you can enable ob_gzhandler for all your pages. If you have a lot of other text files (e.g. .html), then it's better to have mod_gzip and just disable PHP's built-in gzip compression.
And keep in mind that not all control panels will pass the bandwidth savings from gzip compression on to you. The host may be saving bandwidth, but you'll see no difference in how much bandwidth is being charged to you before and after mod_gzip. I know CPanel calculates bandwidth before mod_gzip. Ensim does too, but last I heard they had a fix for that.