Too many variables to give you an answer.
6sec
one day well it depends on the car . The better the car the more days,months or years it would need to be built
25 years
a year
25 years
40 hours
I ordered from GM and I got a car in three days
My guess is about a week because a car is so big and it takes about a week to build truck.
How long would it take a car to travel 87 kilometers if it were travelling at 90 kph
2 hours by car
I would suggest building a motor first.
It would depend on the car's speed.