i had a cayenne turbo in the old concept and i also had the chance to test and drive new turbo, new S, new hybrid etc... as always..... it's always a question what you surch.
If you want speed, good grip, acceleration very fast, then go for the turbo. If you are looking for speed, good grip and normal accelaration go for the S. For the other i do not pronouce myself.
I decided to shoose the S cause it brings me what i need for a daily bases SUV. I don't need 500 HP. I got the GT3 for play or get sensations. Now if you do have only one car and again you are looking for pure sensations and pleasure get yourself the turbo otherwise get The S.
With my S i do find almost the same sensations that i had with my old Turbo but i can't really compare cause the new cayenne is a new Cayenne and has a total different behavior then the old one.
Then last thing. if it's not a question of monney and you do not have to calculate with insurance, fuel etc.... get yourself the turbo or like RC said, get yourself a early second hand one.
Hope it could help.
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GT3, Cooper S & CS