Which intake would you use?

Hang on guys; with a manual trans, the engine is married to the tires.
The starter gear in this instance is 2.66x3.23=8.59, which is brutal for a 318 to pull.
If it had an automatic, then it would additionally have the TM (Torque Multiplication) from the TC which at zero mph can typically be plus 80%, and diminishing rapidly with speed to something like plus 40%, eventually hitting a low of perhaps plus 8%.
Furthermore, the automatic is never required to pull hard below stall.
But with a manual how do you drive below 30 mph? with 3.23s ?
I'll tell you; with 27" tires; 1000rpm is already 9 mph. Think about that. 20 is 2135, and 30 is 3200. So every time you slow down, you are gonna be in these ranges.... in first gear. So if you want to accelerate from those rpms without bogging or hesitating with the 318, this demands low-rpm torque, or a slipping clutch.
Low rpm torque with a given engine requires cylinder pressure and the air has got to speeding thru the intake to get to it's destination, especially at low throttle openings, keeping it's fuel load in suspension.
OP says the engine is a 70, so it does have some compression, and the cylinder pressure on those is a lil higher than the smoggers. That means, the intake is the second last tool to making torque, the primary venturi size being the last. Since the performer covers both bases, to me it's the logical option.
Those 3.23s are gonna dictate the choice.
Now we get to OP's stated useage; namely cruising.
With 27"tires, 65=2610. With a hi-compression 318, and proper timing (which could be in the 50s), the throttle opening is gonna be pretty small. Now the smaller runners are really gonna pay for themselves, with runner velocity, keeping the AFR relatively stable at cruise. And that means you can lean it out, and that means more miles per unit of fuel used.