I don't know what world you guys live/work in, but if a guy (with lots of money) usually you boss.... wants a car modeled in 2-3 days..... someone is going to model a car in 2-3 days.
And if it isn't you, well then, that's your loss... I'm sorry but in this day and age, if you can't do it in the time given (if any) someone else will.

A week is a good estimate as for time slot though. And that's for an individual. And of course that's just the modeling, and maybe some basic rendering.... No animations.

It's good to test yourself against a time limit, but don't let your model suffer for it. At this point in time, it would probably be best to take the time, and make the model look top notch. Then worry about deadlines, when someone hires you to build them a car because they saw your previous work.

Anyway, nice model. Keep at it.