Is there any thing other than a Pax supercharger that will let me get more hp out of my 2000 passat v6?

Uhhh does paxton even make a supercharger for that engine? If they dont then there is no reason to make a custom kit. Honestly, this is not an engine that you will want to mod. A 1.8t or a VR6 actually have aftermarket parts that are available, and are much superior to the Passat v6.

But on any engine, an exhaust system, and maybe a cold air intake will help.

http://www.sfxperformance.com/parts/NEU641062.htm
Plus Cat back, K&N air filter or NEUSPEED P-Flo.

PES makes a supercharger, never heard of pax.

ANywho you can get the regular bolt ons, cold air intake and catback exhaust along with a chip from either apr or neuspeed i believe. But you will likely only see a 5-15hp increase after 800 spent.