C- gussets are supports for your front axle "C's", they help keep them from bending (you will need to source a welder for this install)
Something like this:
http://www.offroadevolution.com/product/evo-mfg-front-c2-knuckle-gusset-kit-weldon-jk-jku/
As for the 4.88s, those are axle gears. 4.88 is the ratio. You will need the 4.88 ratio gears for your axles, plus master install kits (trust me, you want the master kits) a phone call to Wes @ trail jeeps will answer all your questions on the parts. As for install, you can take it pretty much anywhere that does gears as I Unfortionately do not own the tools to do the job. Should be about a 2 day job. When the time comes though, hit me up. I might know a guy
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