How does the S model make extra power over the non S model? Is it software only or larger turbos etc? Regardless if I was In your position i would 100% spec the S version. If u are spending over 70K already then really another 5K isn't a huge Amount. Without a doubt an S version will be worth more than a non S version in the future. Also if the S comes stock with those AMG buckets then it works out really well. Why don't u go for an S and spec the carbon trim. Will be worth it when u have the car, trust me..