I just picked up a 2006 Turbo S 4-6 weeks ago and love it. Long time Porsche owner, but this was my first Cayenne. I asked some very similar questions on the forum and received a lot of excellent info here -->
http://forums.pelicanparts.com/porsche-cayenne/745828-just-purchased-06-turbo-s-suggested-replacements.html
Travis is excellent and covers most of the "what to watch out for's" at the link above.
As for some of the other questions you have, from my brief experience I prefer the Turbo S, but then again I always like that little extra. The Turbo S has an extra ~70 Hp and some other features, but it sounds like you are aware of those. You start out ahead of the curve a bit with the S, but then again, if you are going to do a ton of performance upgrades, you will be sitting in a similar spot at the end of the day going with a turbo.
I spent two months crawling all resources to find mine, and if you play your cards right, you can get into an Turbo S for the price of a turbo, so why not? You will know it when you find it. Oh, and as I am right next door to you in Montana, I bought my car sight unseen out of NY and had no issues. Even though we dont have the selection of Porsche Shops, there is a fair amount of quality information out there on the Cayenne. The back of the center console has the seat heater controls. The adjustable suspension is by the transmission shifter. I can send you pics of these if you wish.
I am already planning to do a handful of adjustments, mostly for fun. I have spent a fair amount of time preparing to do the coolant pipe update and will be doing this my self in a month or two.
I also plan to upgrade some exhaust items, upgrade primary cat, bypass secondary, IPD intake, different filters although I am not sold on one exactly yet. A full brake kit is coming as well once I make a decision and ECU.
White was the last color I thought I would ever own in a Porsche, but I like the factory blacked out trim, and was sold. I have already added the clear Euro markers and going to do a set of flat black wheels in the techno style. Let me know if I can do anything further to help in your quest.
Cheers
Jesse
http://forums.pelicanparts.com/uploa...1372292514.jpg