Easy ones first-
KYB shocks are garbage. They're too stiff and ride like crap. If you want good shocks, spend the money to get RCD Bilsteins. If you want cheap shocks, just get the replacement Monroe's or Gabriels, they ride nicer than the KYB's and cost less anyway.
The Hellwig sway bar will fit better and have much better hardware and instructions than the Addco bars. The majority of the load on a hollow bar is carried on the outside, so the reduction in roll resistance is small compared to a solid bar of the same outer diameter. Plus, you may not need the larger bar anyway, that will depend on your tire choices. If you're keeping 15" rims and the tires that typically go with them, you're not going to need a gigantic front sway bar. That said, I run 1.12" torsion bars and a Hellwig sway bar on my '74 Duster with 275/35/18's.
Now, poly bushings. There are a lot more considerations than just "they're easy to install because you don't need to remove the bushing shells". So this will be long...
Poly LCA bushings do not work the same way that rubber LCA bushings do. Rubber LCA bushings are an interference fit between the outer and inner shells. Because of that, nothing spins/slides. Which means that the entire travel of the LCA is flex in the bushing. That's why you have to torque the LCA pivot pins at ride height, because the rubber will not flex enough to cover the entire range of travel of the LCA- so half the travel is flex up, half the travel is flex down. Torque the LCA while it's hanging down all the way and the rubber will tear before the full travel is achieved, because the interference fit at the shell has more strength than the rubber does in shear.
Poly bushings however are a slip fit. The material is much harder, and does not flex (much). This means as the LCA goes up and down the LCA pivot pin
rotates inside the poly bushing (or possibly the bushing rotates in the shell, depending on which fit is tighter). Because you have one surface spinning/sliding on another, you need lubrication. This is why poly bushings are installed with grease.
Which is better? Depends on what you want. Rubber bushings allow for a lot of slop, the LCA can flex up and down like it needs to, but it also flexes forward/back (this part also depends on the strut rods and their bushings). But the rubber is maintenance free, no service required. I'd say the fit doesn't matter either, so while they require special procedures to install/remove you just install them and it's fine. Unfortunately some of the rubber bushings are made so poorly now that's not the case. See here...
LCA pin loose in bushing
Poly bushings do not allow nearly as much slop. You get more accurate handling, less variation in your alignment changes, and sharper transitions from your steering and handling inputs. BUT! They
must fit tightly in the shells, and tightly on the pins. If the bushing is not a
tight slip fit into the shells and onto the pin they will wallow around, which will handle like crap and wear out in short order. Because the shells are original, that tight slip fit is not a guarantee, you have to check. And if the fit isn't a tight slip fit, you have to change the shells. Also, if the grease dries up, they will squeak!!! If they're squeaking, that's friction, and that will wear out the bushings prematurely. So when you see people complaining about their poly bushings squeaking that's either an improper installation or improper maintenance, and
both will lead to failure. Poly bushings must be greased. Typically a lot of people can get away with adding copious amounts of grease on install, and then not again for a long time. I always install poly LCA bushings with greaseable LCA pivot pins, so I have a way to add grease later. Because if at ANY point the poly bushings start squeaking, you have to grease them. If you don't have greaseable pivot pins, well, you have disassemble the LCA and add grease. Properly installed and maintained poly will last forever.
Bottom line for me is I always install poly LCA bushings with greaseable pivot pins and adjustable strut rods. Properly maintained they'll outlast and outperform rubber. But like any performance part, they must be installed and maintained properly, and that goes beyond what it takes to care for OE rubber bushings.
