1 can did 2 sail panels, the seat belt retract cover and both side panels in the back seat. 3 cars should do the whole interior. I am not sure why they recommend adhesio promotor for the color chanfge, it's the same material. I sent from Navy blue to Firethorn and it covered very nice in 4 coats on my sail panels. All the parts for 3 light coats and one heavier coat for the last one.