Cold air intake VS. Individual stacks? (ITB)

[monza]

Need to replace one of the intake boxes on my Harrop so I'm researching which is better, the cold air intake pictured below or individual stacks. I guessed cold air intake. Looks like I may be wrong and individual stacks are better due to some pressure build up in the 'central air' set up.
Any one have the definitive answer? I've searched so much and read so much tech on ITB's and intakes my head hurts. Better = more HP and maybe drivability?- maybe.
thanks!