As mentioned the Spacers are fine when properly installed. I use them on both of my JKU's.
2012 JKU - Tigger - 6-Speed, 3:73 LSD, AEV 2.5" w/Geo brackets, GYD 285-70-17, Bestop Bumpers front and rear.
2013 JKU OM - Oscar - Auto, 3:73 LSD Freedom Edition - AEV 2.5" w/Geo brackets, GYD 285-70-17, Poison Spyder spacers, DV8 Bumpers.
2014 Patriot - Daughter's
2014 Patriot - Son's