I recently purchased a B reg Mercedes-Benz 190 2.0-litre carburetter model with only 26,000 genuine miles and have since done another 15,000. Everything is absolutely fine apart from the fuel consumption which is horrifying.

A few folk, mechanics and enthusiasts included, have told me that upgrading to a newer or aftermarket carburettor might improve fuel efficiency. Would you agree? Also, in your opinion would such an upgrade have any affect on performance or insurance (ie would this count as a modification)?

Also I seem to be going through a lot of oil - adding a litre around every three months. Does this seem normal? There is no smoke or leaking that I can see (either in the engine bay or on my parking spot).