Nissan Skyline BNR34 GT-R Garage Yoshida Roof & Floor Set

Can be installed without this much variation.

If you can remove all the seats and turn the carpet half by half, you can install it.

(Although it is a model-specific design, it is not packed up to the very end for ease of construction.)

The particular point is this material developed by Daiko Rubber.
It is a double structure of materials that are effective for both soundproofing and heat insulation.
If it's just soundproofing, a lead mat often used for audio etc. works well, but weight is very important as a material to be installed in a sports car.