That was a very apt analogy; about the kettle!
I always think that rebuilding a classic is like watching paint dry, or watching grass grow. You never truly become aware of the beauty of the creation until you're done with it. Which, again, is a bit of a misnomer, since you never truly ARE "done with it". 
Are you planning on keeping the stock drive train? Personally, I'd love to see a 200 km/h, 6 second Merc on the roads.
And if you are planning on abandoning stock mechanicals, what do you have in mind? Even if you deviate from the well-beaten path, I'm sure that there is no dearth of more modern, more efficient, more proficient Merc engines in Pakistan. Something to give this beautiful car some real fire in the belly!