that's the one, I used their printable form:
http://www.texasworldspeedway.com/mscmail_print.htm
yeah, you're joining the MSC, whatever that means. LOL... there is no option for $150 on the form, but you can just write it down there. You can email Rusty at that email address to make sure he knows about that.
I usually drive back and out there again Sunday morning.
--Andrew