These 2 Hot Wheels were collaborations between Hot Wheels and designers.
For the Hammerhead, it was designed by Dale "Hammerhead" Earnhardt Jr. and it is supposed to look like a hybrid between a classic '50s hot rod and a '60s muscle car. I bought this one because I didn't already have this 2011 new model and it did look cool.
For the Imparable, it was designed by Jorge Lorenzo and it is supposed to be a motorcycle and sports car combination. I already had another one of these in blue but since I found it to be really neat, I had to get this one in black. And if you can't tell, the driver and his seat can sway side to side just like a real motorbike that is making sharp corners, pretty awesome!