Sir, there is one small shop or a cabin to be more precise with a size hardly exceeding 5x5' and is located at the back end of Tibet center inside a narrow passage that leads towards the M.A Jinah road.
Shop name is madina autos (if I recall correctly) and the shopkeeper is an old man, as per his statement he only keeps original stuff. Price is very reasonable, I bought two sets of NGK BKR6E-11 plugs from him for Rs 130/piece a year ago.
I will advise the OP to do check these two shops ( fair autos and madina autos), if he missed them in the first go.