Most likely same class (another CLA AMG). The general policy is they exchange for the same class car you brought in. I would still try to advocate for something better. If you rly want an American V8, you can go back to LAX to ask for an exchange. I would have asked for a discount when you picked up to downgrade from the "guaranteed" HH Camaro (Hertz class V6) to the regular Camaro SS/Mustang GT/Challenger RT (Hertz class V4). They also have American V8's under Hertz class U4 (Camaro SS/Mustang GT convertibles). If you're rly unhappy you can also try to take it up with Hertz after the fact, upon return or by calling Customer Service, to ask for a partial credit since you didn't get the "guaranteed" class as advertised, but that's also not a guarantee that they would give you a favorable resolution.