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Assuming that you don't have an unlimited budget for Penskes, it seems more and more guys are looking at JRI. They are around $5K, but anything substantially less than that really won't get the job done. In any case, once you go coil over you will need to have them serviced at least once per year.
There is a lot to be said for the stock style divorced spring/ shock, unless you need a performance edge.
One thing to note is that CorteX packages typically use a true coilover in the rear (spring around the shock body), whereas Vorshlag uses a height adjster and spring in the factory rear spring location on the axle. Not having the spring on the shock creates a small amount more room for wheel/tire to the inside of the wheelwell, if that's a concern.