People who buy Hondas and Toyotas do it for reliability and ease of mind. First of all you can't buy a 'decent' C Class for the same amounts, a good peice will run you upwards of 2.5 million rupees (for a fairly recent model).
Secondly, if you think buying a 1998 C Class is a good idea compared to buying a CL9 or Mark II/Mark X, then you're deeply mistaken as the maintenance costs on that alone will be insane. Furthermore no way will a Merc from that day and age be comparable to a CL9 or Mark II. Those cars are trucks to drive compared to the Japanese wonders.
If you want to buy a Merc do it when you can afford to pay the same amount that you paid for buying the car for the upkeep of the car. And if you're really going to buy a Merc at least get an E Class 
One should buy a car that he can keep scratchless and in mint condition. If your car is going to end up looking like a crap-bucket, better to buy something which you can maintain. Atleast it will look good!