Have you upgraded since the teins, cos I remember they were in it then.
Trying to arrange everyone in a particular way most likely won't work, what with the amount of comings and goings there tends to be.
Rows and back to back with someone else would probably work best, at least that's what I've noticed from past years.
It'll probably be really tight if there's going to be more cars.
Probably try to stick with two rows, side by side, back to back, that way people can come and go. I can even bring a string if you really want to make it pefectly lined up, like the japs do.
If your really tricky, you could even try and put an angle on the cars!