Turbulence in the intake is another old school thing that should really go away.
Back in the days of carb's, you need that turbulence to properly mix the fuel into the air and get a cleaner burn. Thats why oldschool intakes had that rough texture inside them and the intake ports were rarely POLISHED.
Shorter runners make more horsepower, longer runners make more torque. Thats the simplest way to describe what goes on.
In a modern engine, you can extrude hone the intake manifold and ports and if you have your injectors sized right and the tune is spot on, then the correct mixture will happen anyway. On a honda, with the pent roof design if you extrude honed everything and unshroud the valves slightly, you get a BEAUTIFul tulip entry pattern, and the design of the cylinder head then squeezes the entire mixture up to the spark plug gap. By mirror finishing the entire intake, you would increase the velocity(as long as you didn't open the ports up to large) thereby creating more low end and high end power.
That brings us to runner size. If the runners are to large or the ports opened to much, you lose velocity, and thereby hurt your low end numbers. Lots of R&D goes into making a factory car's intake and exhaust ports JUST right for day to day applications. Just the right port size, shape and finish(rough, polished, mild) to get the best hp/tq numbers for the best price to sell a good reliable around town hill climber with a little bit of pep when you ask for it.
For an all motor build, the thing on a honda you really need to concern yourself with is low lift porting. Honda spent alot of time making B/H/K's flow well at high lift, not so much on the low lift. You can have someone witha flowbench, slowly rework the ports for low lift flow and gain considerable numbers without loosing the velocity you require for that off the line bite. If you are building a track car that launches at 5000+rpm's and never goes below that for the most part or a boost monster then, by all means, hog that @@#$@#$ out
/2 cents.
I got tons of information up here.. and no time to use it =(
Dave