Do you mean the 1/18 HotWheels Tumbler? I own the one from Batman Begins, the one with the black exhaust pipe. And that one is nowhere near as accurate as the 1/6 Hot Toys Tumbler. The front wheels on the 1/18 Tumbler are too big compared to the rear wheels. And the interior is just a piece of black plastic. Besides you can tell by only watching the car is made from two different materials metal and the roof of the car is made from plastic !!..
And the 1/6 Tumbler can fit a 1/6 Batman
.. which is the best part.. I always wanted an accurate Batmobile where my batman figure could fit. I remember my Kenner Batman & Robin Batmobile, and my batman figure wasn't able to fit inside the car with the cape and it's arms didn't fit well too.