Reply to "Vague steering, need help!"

First thing I would say is that your spring rate is way too stiff.
I do know its personal preference & some may disagree.
But a stiff sprung car will be a very harsh ride & will tend to skip/dart around on bumps.
With stiff springs you have no choice but to run really stiff dampening settings to control the spring’s energy.
A softer spring set up will give a much better ride & better compliance to the road surfaces.

As far as darting from one side to the other on brakes.
This is likely a toe issue & your car may have” toe out”.
So whichever wheel happens to be steering outward at the time the car will dart in that direction.
Slight “toe in” will give much better tracking on hard brakes.

Wide front tyres do tend to want to trammel in ruts.
(Different tread patterns affect this also, some are better than others).
A lot of outward offset of the front rims can make the front too sensitive to road irregularities.
With a lot of outward offset, (rims widened outward) when the wheel hits a slight bump at the outside of the tyre the bump tries to steer the car in that direction.
Stiff springs just make this situation worse as with a stiffly sprung car the wheel hardly moves & the car then follows the bump.
Where as a softer spring allows the wheel to move upward & ride over the bump & be less affected by road surface conditions.

“Toe out” can produce under-steer as the outside front wheel is steering less in the corner.
So it feels like you need to wind on more steering to get yourself around that corner.
With “toe out” both wheels are slightly steering outward when the car is pointing straight ahead.
If you steer right for example, because the right wheel is already slightly steering right its turn to the right is more exaggerated.
Where as the left wheel will not steer to the right as much.
So what you end up with is an exaggerated Ackerman.
Because the cars weight is thrown to the outside of the car in a corner the left front wheel will have more traction than the right front wheel.
So in effect it’s the left front which is the wheel doing most of the steering work to steer you when steering aggressively right.
But if a “toe out” situation exists then the left front wheel is actually not steering as much as it should be as its steering angle is reduced.
Which can give you that under-steer feel.

I’m not familiar with the term “bobbling”

In reality what the Pantera needs to correct its steering faults is more Caster, more kingpin inclination. (Which would require the axle to be at a different angle to the upright).
And longer suspension arms so the front wheels don’t need to be widened so far outward to match GT4/GT5 front flared fenders.
The rack & pinion is also too long with the rack ends being too far apart.
If a line is drawn between the top arm pivot point & the lower arm pivot point the centre of the rack end ball joint should intersect this line.
With the Pantera the rack ends are way outboard of this line, which causes bump steer.

Lowering the nose of your car is canceling out some of the Caster angle, in which the Pantera has very little to begin with, maybe 2 degrees at most.
(Johnny Woods front top arm modifications to increase Caster would be greatly recommended).
So a nose down situation, combined with a lack of Caster will make the car tend to feel flighty at speed.
That is, you find yourself constantly correcting the steering & bringing the car back to a straight ahead direction.
Modern cars have more Caster, if you let go of the steering wheel the wheels tend to centre themselves, (self centering steering).
Also, another effect Caster has is to increase cornering traction.
With Caster the wheel arcs downward as the wheel steers outward.
Effectively the wheel is jacking up that corner of the car.
This is why Caster makes the steering heavier & requires more exerted force from the driver to steer.
The increase in cornering traction is due to the jacking effect.
So again let’s assume we are still steering right.
The right front wheel arcs downward which lifts the front right of the car, which in turn transfers weight to the left rear wheel.
This transfer of weight to the outside rear wheel increases its traction & helps you turn into the corner.
This technique is used a great effect on off-road vehicles & Sprint cars to help steering in loose terrain & it does the same thing on street vehicles.

Sorry for the long winded reply, suspension is my thing as I design off-road race buggies for a living & get a little passionate about the subject.
These are also just my opinions & should not be taken as Gospel.

Regards,
Tony.