I think I read that the Attention Assist is a feature where the CLA will be able give more power ratio to the front or rear wheels if it needs it or not. This means the CLA will have the ability to give 100 percent to the rear if necessary. For a few moments the CLA can be a RWD car .All versions of the CLA are front wheel drive. The 4MATIC is front a majority of the time and only rear power will come during major front wheel slippage.
What is the ATTENTION ASSSIST feature?