Only RRO offers a spacer lift kit. Eibach has a spring kit. Search the forum for those and you will see plenty of discussion. I think there's a couple lift right ups in the modification and build thread sticky. Read through the tire and wheel stickythreads for wheel/tire/spacer advice and discussion, its a popular discussion topic here.... your question has been asked and answered hundreds of times, no new developments over the past few months.... and there are as many subjective opinions as there are wheels and tires.
Check out the forum vendor page. Kolak can offer some Grand Cherokee advice.
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