I very much agree with what the OP said in his turbo versus GTS paragraph, although when pushed very hard understeer occurs in the GTS later and with more predictability given the lower center of gravity. And if the lower center gravity is important to you, a turbo with air suspension can easily be lowered… Or you can look at the turbo PP, but that's even pricier.
If anyone is on the fence between these two models the best thing to do is drive them back to back yourself, and also price out each model back to back the way you would actually want them.
Is the turbo worth the extra money? It's an individual decision. I was ready to order a GTS, but then I took long test drives in the two models back to back. And now I am contemplating a Cobb tune as even the Turbo doesn't feel as fast as it really is.
One thing I suggest you keep an eye out for with the GTS is the standard seat. While it initially felt comfortable, after about an hour it was not, and at least a couple of professional reviewers have made the same comment. You will find substantial discussion here on the forum comparing the 14 and 18 way seats, which are both available at no extra cost on the turbo.
'16 Turbo,Sapphire,Black Leather Int/Sport Classics/Window Trim/Roof Rails/Xenons, PDLS+,Tinted Tailights,Sport Design,PSE/PTV/AS/SC/ACC,Burmester,Prem/Comfort Lighting Packages,Leather Dashboard Trim,Seat Console,Steering Column,Rear View Mirror and Sun Visors, Leather Interior Trim in Pebble, Pebble Seatbelts, Headrest Crests, Armrest Logo, White Dials/SC Clock, Alum Fuel Cap, Spt Design Mirrors, Surround, Connect/Online Services,Painted Key,Leather Keypouch,Illum Door Sills