I think you are confusing a busy interior (with all these geographic lines everywhere in the NSX interior) with cheap.
If you get the C7 upgraded interior package both interiors will have stitched leather and carbon fiber (which I think is sooooo overplayed these days).
So far here are the details that I can find:
1YY07 Corvette Stingray Coupe $51,000.00
1YX07 Corvette Stingray Coupe w/ Z51 $53,800.00
1YY67 Corvette Stingray Conv $56,000.00
1YX67 Corvette Stingray Conv w/ Z51 $58,800.00
Destination Charge $995.00
1LT Base Equipment Group 1Y*07/1Y*67 $0.00
2LT Equipment Group 1Y*07/1Y*67 $4,210.00
3LT Preferred Equipment Group 1Y*07/1Y*67 $8,005.00
D30 Custom Color and Trim Combinations $590.00
PIN Customer Selectable VIN $5,000.00
R8C Corvette Museum Delivery w/Interior Plaque Includes CFX (Plaque) $990.00
ERI Battery Protection Package $100.00
J6E Yellow Brake Calipers $595.00
J6F Red Brake Calipers $595.00
NPP Exhaust System Performance $1,195.00
VK3 Front License Plate Bracket &R7E $15.00
FAY Carbon Fiber Interior Appearance Package &2LT/3LT $995.00
IL4 Sueded Microfiber Seat Inserts &2LT $395.00
IL6 Sueded Microfiber Seat Inserts &3LT $395.00
IWE Sueded Microfiber-Wrapped Trim Package &3LT $995.00
UY4 Chevrolet MyLink Navigation System &1LT/2LT $795.00
G7H Laguna Blue Tintcoat $995.00
G7J Lime Rock Green Metallic $495.00
G8A Velocity Yellow Tintcoat $995.00
GBE Crystal Red Tintcoat $995.00
C2M Carbon Fiber/Transparent Dual Roof Package 1Y*07 &2LT/3LT only $2,995.00
C2Q Body-Color/Transparent Dual Roof Package 1Y*07 &2LT/3LT only $1,995.00
C2Z Removable Roof Panel, Visible Carbon Fiber with body-color surround 1Y*07 &2LT/3LT only $1,995.00
CC3 Removable Roof Panel, 1-piece Transparent 1Y*07 only $995.00
AE4 Competition / Performance Sport Seats Without Sueded Inserts $1,995.00
AE4 Competition / Performance Sport Seats With Sueded Inserts $2,495.00
TTV Carbon Flash Painted Spoiler & Outside Mirrors $100.00
FE4 Magnetic Selective Ride Control w/ PTM 1YX*7 only $1,795.00
MYC 6 Speed Paddle Shift Automatic Transmission $1,350.00
Q7E Chrome Aluminum Wheels 1YX*7 only $1,995.00
Q7T Black Painted Aluminum Wheels 1YX*7 only $495.00
QX3 Chrome Aluminum Wheels 1YY*7 only $1,995.00
RQ1 Machine Faced Aluminum Wheels 1YY*7 only $1,495.00