If you have a V 10+ in the US the racing shell seats are standard. They are not available on the regular V 10. If anything, I would consider the racing seats to be an upgrade rather than a downgrade. Now that being said, it is a fact that most people have come to believe that the buckets are more comfortable. I haven't sat in either version. I think it comes down to what you plan to use the car for and where your mind is that with respect to experiencing the car. I have spoken in detail to people that have driven the car with the racing seats.
Of the many comments I heard one did stand out- "The car was so fast that when I drove it I was glad to have the support of the racing seats ". For this reason I have decided to keep the racing seats. Also, on my current car one regret I do have is being unable to fit a four point harness without having to buy brand-new seats. By getting the shell seats that will be easy to do, even though I only track my car a couple to three times a year. Believe it or not, those precious minutes on track versus the rest of the year seem to stand out more and more powerfully on my car ownership Experience then all the relatively invisible and uneventful commuter miles spent in the car the remainder of the year. The consensus I get is that the buckets are more comfortable overall but it's not like the racing shell seats are torture contraptions from the dark ages either.
Ideally I would love to have contrasting stitching everywhere in the car but I will be happy with the contrast stitching that comes as standard on the racing shell seats. Seeing as how this is going to be my third R8 I have learned very well how quickly the interior becomes invisible when you're driving this amazing car on a quiet Sunday morning or to and from work.
I will be doing the extended leather package. But it does not include contrasting stitching on the dash or doors.