is there any way to alter the way a power steering system feels (how heavy the steering, etc) by fiddling with the pulley sizes on the PS pump? for instance, if I wanted to add a bit more weight to the steering on the Miata (it feels VERY light, not uncommunicative but almost too much assist for my tastes), would it work to put a slight underdrive pulley on the PS pump and re-tension the serpentine belt to suit? or would this seriously mess with the overall feel of the steering and compromise the PS system?
from time to time, I get these weird curious streaks, and weird ideas pop into my head... and usually they go away, but normal, everyday conversation has to take a slight detour before it gets back on track... 
A smaller steering wheel makes things quite a bit better on a ps miata. The issue is getting a wheel that is smaller while allowing you to still see the gauges.
You should be able to alter the overall pressure of the pump through changing the pressure oriface size or shims. Most stock pumps are over pressurized from the factory to get "90yr old Ethel" to be able to turn the wheels while stopped.
Brian
The pump has way less to do with the feel of the steering than the rack does, and thats built into the valve body of the rack- usually some sort of torsion bar that move the valve. In the olden days, GM steering boxes had a bunch of different sized torsion bars, ranging from, say, Corvette to DeVille.
On the topic of weird ideas, I've heard of people that remove the ps pump altogether, and connect the ends of the hoses together making a loop. Presumably, they attempt to keep the system full of fluid. Voila! Instant manual steering.
Things that effect feel
King Pin Angle
Alignment
Friction in the System (From steering wheel all the way to the road)
Pump orifice size
Pump Speed (High RPM engine develop a particular problem due to cavitation.)
Steering Shaft Geometry (Wheel to rack)
Steering linkage geometry (Rack to wheel)
Rack type
Wheel size.
Hey look I got some use out of my college project!
FYI: Did you know the steering feel of the new Accord is based off of a 2003 Focus ZX3 with PZero Nero tires? Fun fact even Honda doesn't know.
Add a by-pass line and a regulator.
GM's that used a saginaw pump it was easy to remove the presure relief valve and alter the spring presure to suit your needs.
70's MOPAR's i added the by-pass and adjusted for good feel on the hi-way.
44
Changes to the caster in my alignment drastically changed the steering feel on my miata.
The PO had caster around -2 degrees, when I had the car realigned I had it set around -5.5 degrees
Also there is this option....
http://www.flyinmiata.com/tech/depower.php
I have actually considered attempting to just "loop" the lines on my Accent, the steering rack setup is quite similar to the miata when I compare the pics on the FM walkthrough and Hyundai FSM pics.
