I have a 70 Coronet 2dr HdTp.. that I have owned since 1982
318 engine automatic 8.25 rear end 2.71 gears....

Suspension wise:
I use the mopar performance 0.96 torsion bars (Hemi size)
mopar performance hemi-leaf springs
Billstein shocks
stock strut rods
stock tie rod ends (from MOOG)

I added boxed super bee lower control arms
1 added the front sway bar (from firm feel)
I use the stage 2 steering gear from Steer-n-gear
I tried the borgeson setup...and it just hissed and hissed
and after months of total frustration, I sent it back and got my money back...

The stock caster setting of 0-1 degrees sucked from a "tracking straight down the road" standpoint.

I first tried the MOOG offset bushing on the stock UCA's
I was able to dial in 2.0 on the driver side and 2.5 caster on the passenger side.
This was a very noticeable improvement over the stock 0-1 degree setting.
Overall, a cheap upgrade that worked out really well...

After years of hearing more caster is better
I went ahead a bought the FirmFeel arms, and installed them

I can dial in 3.5 degrees on the driver side and 4.0 on the passenger side..
After driving for over a year (about 1000 miles)

I can tell your this: FWIW... I think the car felt better with the offset bushings...
I guess my car doesn't need all that caster.... 2.0 - 2.5 degrees seems to be plenty for my setup...
I just don't notice any real improvement tracking straight down the rod by upgrading to those FF arms...

However, I have not removed them...
I kept my old (stock) UCAs just in case...

If I had it to do all over again I would pass on the FF UCA's...
I might however consider the Hotchkiss setup which is REALLY pricey
but can jack up the caster to 6-8 degrees (so i'm told)

The FF is better than stock..
So I feel no need to change it out... yet


Hope this helps