I have a property that I intend to let out on a monthly rent of Rs.1,00,000/-. Is it OK if the Rental Agreement is written down, signed, and witnessed on a Rs.100/- non-judicial stamp paper? Or, should I necessarily get it registered? Also kindly inform me whether the ENTIRE 'Contract of Rent' gets invalidated MERELY because the doucment is not sufficiently stamped. Kindly advice.