I'll spare you the lecture on the coilover systems, replicaracer43 hit it solid. The fastest Mopars still run torsion bars.
The Hotchkis TVS is the closest thing you'll find to a complete "kit" for torsion bar suspensions. That said, it's missing some really important stuff- torsion bars and shocks, for example. It also has some stuff you don't need, like the steering links. Sure they're nice but they really aren't necessary and they won't actually improve much. Hotchkis also has heim jointed UCA's. Long story short, I've found that heim joints don't work all that well for a street car that sees a lot of miles. My first set of Hotchkis heims only lasted 7k miles, my second set did another 7k but probably won't see 10k miles. At the UCA I don't like heims. At the strut rod they're not an issue, the heims on my Challenger's adjustable strut rods have 70k miles on them. Go figure.
Anyway, Hotchkis makes really nice stuff but it's also pricey. So, while there isn't a kit I can give you a list. Firm Feel makes great torsion bars. So does Sway-Away, and so does PST. The 1.03's that PST sells are about $100 cheaper than comparable bars from Firm Feel or Sway-Away, and they're a good size for a street car that isn't being set up for aggressive handling. A good all around bar that won't rattle your eyeballs loose but will still bring your Mopar's handling into this century.
Suspension work:
1.03" (or bigger) torsion bars ------------------------$250-$355
Tubular UCA's (PST, FFI, etc)------------------------$350
Adjustable strut rods (PST SR 14385)---------------$279
Solid tie rod sleeves (PST SAS 440S)----------------$49
LCA boxing plate (PST LCAPLTMOP621)-------------$14.50
Greasable LCA pins (FFI w bushings)----------------$135
Helwig tubular front sway bar 1 1/8 #5906 or 55917 (better tire clearance than the 5906) -- $256
Solid rear 3/4 #6907--------------------------------$237
Rear Springs: 0 arch, something in the 120 lb/in to 130 lb/in rate
Energy suspension 1" shackle bushings 2-2117G----$9
Bilstein RCD shocks(RCD-70-56663)------------------$410
Grand total on that is about $2,300, that's got a little extra built in depending on where you shop and what you buy. These prices are a little old at this point, you'll probably find they're a little higher now.
Chassis work:
Subframe connectors (1.5" x 3", .083" to 1/8" wall)
Torque boxes (US Cartool)
Shock tower to firewall reinforcement (US cartool or tubular "J" bar)
Lower radiator support reinforcement (US Cartool)
Alignment:
-.5° to -1° camber, +3° (minimum) or more caster, 1/16" to 1/8" toe in
For the explanation- I recommend tubular UCA's because you can't really get more than +3° of caster with the stock UCA's and the Moog K7103 offset bushings. That might be ok for you, but really the car will handle better with more caster. I recommend adjustable strut rods to eliminate binding on the LCA travel. The stock set up is "one size fits most" that doesn't usually fit any particular car all that well, and if you upgrade the LCA bushings you need to tune the strut rod length. I used to recommend the Mopar Oval Track rear springs, but their quality has been terrible lately and I won't recommend them until they improve that. It's a shame because they used to be a good, low cost option for an improved rear spring, the other options like Peter Bergman's Eaton springs or the Hotchkis springs are much more expensive.
US Cartool makes great chassis stiffening parts. The only thing I'd skip is their subframe connectors, because really you need to fully strip the car to install those right. And even then you really need a lift or a rotisserie. Without those, just make your own out of rectangular tube. It'll work just as well, and it will be LOTS easier to install. I've done both, and I wouldn't do the US Cartool ones again.
Brakes:
DoctorDiff sells everything you need for front and rear disk conversions. He sells the full 73+ Mopar conversion for the 10.95" brakes (stage I) as well as everything for the 11.75" Mopar disks (stageII). The 11.75's do require 15" or larger rims. He also sells a couple of 13" disk kits, I have the stage III "cobra style" front disks and calipers on my Duster. I ran the 11.75's on my Challenger for 70k miles as a daily driver too, they work fantastic. And everything is off the shelf Mopar on those. The 13" brakes are definitely an improvement, but they also require 17" or larger rims. DoctorDiff's rear disk kits allow you to keep your stock tapered bearings too, most rear disk kits need to be used with green bearings. And Cass (aka, doctordiff), is super knowledgeable and very helpful. One of the best Mopar businesses out there.
Stage I- 10.95" Front Disc Brake Kit (Stage 1)
Stage II-Mopar 11.75" Front Disc Brake Kit (Stage 2)
I have more details on the specific stuff I've done to my car in my build thread, which is linked at the bottom of my signature.
View attachment 1715315134
