Why the model varies and the class does not.
RYDES works with 3,500 licensed chauffeur operators across 1,200 cities. Fleet composition follows local supply, local taxation and local road conditions. Promising one specific model everywhere would mean either refusing most of the network or breaking the promise regularly.
So the class carries the guarantee instead. Book Business and the vehicle that arrives meets the standard set by an E-Class, a 5 Series or an XT5, or exceeds it. If the operator's Business car is unavailable and the next vehicle is a First saloon, you travel in it at the price you booked. Substitution runs upward, never down.
Where a specific model is genuinely required for a protocol or brand reason, ask before booking rather than after.