Hey Jeff, how long have you run your air pump? I've been considering going with a factory air pump also. Did you get yours modified or are you running it as is? I saw a website who sells modified units for racing but he wants as much as the Moroso pumps for them. I have a hard time paying almost $400 for a factory air pump. Supposedly his mods compensiate for the fact that when operated as a vacuum pump it will see a oily environment and his modifications tailor the internals of the pump to be used in this way.
Have you had to rebuild yours yet? Do you ever drive on the street? Let me know about the mods you made to run it, and if it has any longevity issues that you know of yet.
The place who sells them is:
http://www.gzmotorsports.com/
88:
Definately worth the hassle and money. Especially if you build for it from the beginning using lower tension rings that you would normally run. Net increase is usually in the 20 Hp range but on a dedicated vacuum pump motor it's not unheard of for it to be worth 40hp.