say what would DUAL air filters do instead of just one? would it help the engine? (no im not looking for that extra "HP" but i just wanna make my engine breathe nicer)

 

yeah it be 2 cones hooked to one intake......(2 smaller cones tho)

 

Yes, the more surface area you have to draw air through a filter the easier it will be. Less air has to travel through each square inch (or cm).

But, two air filters is useless added weight. You can get huge K&N cone filters that have a lot more surface area than the standard cone fitlers that are sold for the 280ZX.