Alterkation or K1?

And here we go again.

This whole thing is fairly simple. Coil overs are not magic, they are a spring and a shock. All the conversions out there use Mustang II spindles and geometry for the most part, but there are some changes in geometry with frame mounting width. MII geometry is not inherently better than the torsion bar suspension geometry, both have their pros and cons.

So if you take the geometry out of the picture (and I do), what do you have left for the coilover conversions? A rack and pinion, which feels more modern but doesn’t actually improve performance. More room for headers, definitely. But, there’s still a pretty limited number of headers that will fit the car. Install is easier, but unless you’re pulling your engine all the time that’s a once in a while problem. A small weight savings. I have the numbers, they’re posted here, but it’s less than 50 lbs like to like (as in, not comparing power steering to manual).

There was a time when you couldn’t get off the shelf, adjustable shocks that would be good for the torsion bars. That time has psssed, and there’s no advantage to having coilovers for that reason anymore. There are quite a few great choices for shocks and adjustable shocks that will work with whatever torsion bars you choose.

And finally, price. The price is no where near the same if you can intelligently make a list of parts instead of blindly buying a Hotchkis TVS and then filling in the gaps. These prices are a little over a year old, but I would assume that it’s all gone up fairly equally. I’m leaving brakes out, brake kit prices are fairly similar as well so it’s easier to leave them out of the comparison. Same for chassis work, realisticly you’re going to do some of that either way.

RMS Alterkation w/engine mounts and without brakes - $4,995
RMS Street Lynx - $1,995

Total: $6,990 (keep in mind this doesn't include installing the street lynx, which takes welding)

This is everything I have on my Duster. It's not the cheapest way to do it, although it's not the most expensive either (ie, complete Hotchkis TVS).
Front:
1.12" torsion bars from Firm Feel: $355
Bergman Autocraft SPC UCA's:$395
Bergman Autocraft Delrin LCA bushings: $80
Firm Feel greaseable LCA pins: $135
Howe Racing upper ball joints: $130
Proforged lower ball joints:$80
QA1 LCA's: $395
Hotchkis Shocks: $475
Hellwig 55905 front bar: $175
Flaming River 16:1 steering box: $610
QA1 tie rod sleeves: $50
Proforged tie rods (all): $65
Moog pitman and idler arms: $80
Adjustable PST strut rods:$300
Rear:
Hellwig 6908 rear bar: $180 (this is the Ebody bar I run with my B-body rear axle)
AFCO 20231M springs: $320
AFCO leaf spring sliders: $200
Dr. Diff 1/2" spring offset:$150
Leaf spring perches: $15

Front suspension: 3,325
Rear suspension total: 865

Total: $4,190

So, not even close on the price. $2,800 in savings, and I used most of the most expensive options out there for my car. You can do it far cheaper than that by boxing your stock LCA's, using regular upper ball joints, getting PST 1.03" bars, using a PST manual steering box, running Bilsteins instead of hotchkis shocks, etc. Just those by themselves drop over $1k from the total. So the idea that the torsion bar suspension will cost just as much to modernize is BS, you can do suspension for the entire car and still be almost a thousand bucks ahead compared to just the AlterKation in the front.

Honestly, I don’t care what other people run. Make your choices, spend your money. But from a suspension geometry standpoint, a coilover conversion is not better, just different. From a cost standpoint, it’s not better. You get a rack and pinion, and more header clearance. You give up a lower center of gravity and a suspension that was designed to work with the chassis you have, and that last one is not a small deal. You either modify with aftermarket parts the suspension intended for a Dart, or you modify with aftermarket parts the suspension designed for a Pinto.