I would go with black interior. I have a yellow RT-10 with the brown / cognac interior. I think black interior looks best in any sports car, it looks more racey or sporty. I personally picture tan in a luxury car not sports car.
I must admit the tan / cognac interior in the Gen II cars is much nicer than the Gen I like mine!
I might at one point have all black leather put in and black carpet, cost is about $3000.
But you cannot go wrong with black, no staining, it does not show dirt or stains etc.
Just my .02 Cents.
Here is a picture of tan, picture how much better black would look.
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