Well yea...in the strictest sense of the word..I would not be listening to it in its true environment...and I would probably do a little tweaking once I got back to the car..but at least I could get it close. I'm not just wanting to get a flat level response in the car...I'm wanting to improve the sound, get punchier bass, etc..

It would be nice to work on it graphically, go to the car, tweak it for the car acoustics, go back and look at the curves graphically again, save them ,etc....

It can only help.