I went through the same set of decisions over the course of several years. If you don't plan on racing, I would consider keeping the stock a-arms and get your front shocks re-valved and have dual or triple rate springs added. I had Race Tech do mine and they were really awesome for just riding trails. Price will be about $500-600 but is much less than purchasing aftermarket shocks. Stock A-arms are great because you can always find cheap replacements on Ebay or Craigslist.
NicelyB is spot on and trust me when I say this cause I ate his roost non-stop for about 2 years when I first got my KFX450 many years ago (in fact he took me to my first XC race in Cowpens, SC back in 2009). Start with the factory shock re-valve/re-spring and give it some time to see if it improves anything. If you are unhappy or feel like you need more, you can always add aftermarket shocks and/or upper a-arms only as NicelyB suggested, or even get the full deal with new shocks and a-arms. If you are only into trail riding and don't plan on racing, consider keeping aftermarket shocks stock length and a-arms stock width or +1 versus getting long travel shocks and +2/+3 a-arms (keeps the quad narrow for the trails and is slightly cheaper on your wallet).
For reference, I run X2 Exit Front Shocks and JD Performance MGC +1 A-Arms. My rear shock is stock; I've made adjustments over the last few years to suit my riding style and that's worked for me so far.
Just my opinion.
Will aka "Sweet Willy"
"Self-Sponsored" (just means I am broke all the time!)
Parts that I use and trust:
Precision Clamps, Houser Stem, Exit Shocks, DWT Beadlock Wheels, Maxxis XC Tires, Fuel Customs Intake, Power Commander FCI, Pro Circuit Ti-4 Exhuast, Renthal Sprockets, D.i.D Chain, Tusk Heel Guards, Spider Grips, Kawasaki Factory Frame Skid, Armadillo Swing-arm Skid & Grab Bar, Cycra ProBend, Engine Ice, Mobil 1 & Pump Gas!
Last edited by KawiRider218; 01-03-2017 at 11:20 PM.