I'm running King coilovers and King triple bypass shocks on my JKU. They are EVO spec'd and I've put about 40K miles on them without a rebuild. EVO1 has the same setup, but runs the 6.4 Hemi. You could call offroadevolution (EVO) to see what spring rates they use on their EVO1 JKU. Their setup should work with your Hemi and the added weight. If you are worried about downtime if/when the time comes to rebuild the coilovers, EVO has King bolt-on coilovers that I'm sure they can configure with the correct spring rates for your Hemi. Since the bolt-on coilovers use the existing factory brackets, you could always put your current springs and shocks back on your JKU when you send the coilovers in for a rebuild.