Hi,
All the requested information has been provided in the main rally page:
http://www.mlrc.ca/rallycross/Single Membership: $50 (One person)
Event Prices:
$45.00: Online pre register.
$60.00: Onsite register on day of event.
Car has to be of road worthiness...IE not break down down, and not be obnoxiously loud. If you're getting an Impreza you can drive on the road you would be fine. If its any car you can drive on the road, you would be fine.
No rally license is required for the rally-x events
A snell rated helmet(covered in the rules on the rally page)
No codriver is required, but you can bring one passenger in your car if you'd like.
Again, take a look at the rule page, but the above should cover your questions.