70mm or 75mm TOB for my setup?

Alright so I need some help in deciding which setup my car would most benefit from, a 70mm or 75mm Accufab TOB & Plenum combo.

Here is what I currently have:
Steeda U/D Pullies
Bassani Catted X
Steeda Tri-Ax

Being installed this Sat:
Centerforce Dual Friction Clutch
Fidanza Billet Alluminum Flywheel
Ford Racing Alluminum Drive Shaft
Steeda Clutch Adjustor (Cause you know that improves over all air flow)

For Sure Future Performance Mods:
Bassani Off Road X pipe and Bassani Catback
L/T Headers
Some sort of a CAI like K&N or Demolet
Gears
Performance Heads / Springs
NOS
and a Dyno Tune or programmer like Xcal2

I am riding on 18" Y2K Cobra R's

I don't want the 75mm combo if my setup will not benefit from it. I would rather have the 70mm and keep good air flow/pressure going through my car, but at the same time, if the 75mm WILL benefit my setup, i'd like to know.

What do you all think? (I am looking to make my purchase within the next 3 weeks or so)

No forced induction plans, just a Nitrous kit down the line.

Thanks 4 the replys. I am thinking the 70mm will fit my setup best.