Last weekend before Japfest I finish mine.
4 x Doors - bitum 2mm
4 x wheelarch - foam 10mm
2 x front wings - bitum 2mm
2 x rear wings - bitum 2mm + foam 10mm
Trunck - center bitum and foam+bitum on sides
It cost me about 150 pounds and I jump from 55-60 decibels to 40-45 decibels... measured...