Die Cast cars

What sizes are available for the Mach V and the Batmobile?

I want to get one of my nieces them for X-Mas. I know opening them, they loose their value. Yet I want them to be displayed with her statues and busts. So I guess spending alot of money on a larger one wouldn't make much sense, bring opened. But the smaller ones wouldn't be seen very well, nor be worth keeping in a display.

What are your thoughts?

BTW, besides dolls, she's really into cars. Toys and fair rides.

I bought my niece a Mach V for Xmas. It's a little larger than the one I bought her last month. Looking for the TV Series Batmobile. Our WalMart had all but the 66 version. Is it harder to find? Might get her a "Cars" one in the same scale.