At least with BMW its consistent. A series number (3) followed by two numbers where a larger number represents a larger engine (30/40), followed by X if it has all wheel drive. M means performance. Series numbers increase with price. Pretty easy. Hardest part is remembering which series numbers correspond to which body styles.

Compare that to Merc. There's the C, E, and S-Class which come in Sedan, Coupe, and Roadster variants and increase in price in that order. There's the CLA which is their entry level Sedan, except they call it a Coupe. There's the CLS Sedan which is more expensive than the E but cheaper than the S, and again, is called a Coupe. Then you've got the Maybach name which means luxury, and the AMG name which means performance. Most models have an AMG trim. Add in the E wagon, the AMG GT roadster, the S and SL roadsters, and the GLA, GLC, GLE, GLS, and G-Class SUVs. And the B-Class electric.