Help with nitrous
 

I emailed Edelbrock becaus im kinda intetrested in their nitrous kits and they replied with the following message about it working on a protege dx auto

"Should work if you have a return style fuel system, including a vacuum compensating
fuel pressure regulator".

I know what a fuel pressure regualator is but i dont understand what they mean about a return style fuel system.

can someone help??