Dear Sir,
1. If a buyer buys stamp paper for circle rate and registers at a lower consideration value than the circle rate, then at the time of selling the property in future, Cost of acquisition of the property would be lower and it will lead to higher capital gain tax.
Further, seller of the property will be taxed based on the circle rates even if the registration is done at lower rate.
2. If the registered value is lower than circle rate than capital gain tax will be calculated based on the circle rates. Yes, i think you can pay via cash but you have to show the source of cash when asked for.
3. 30 Lakhs refers to the registration amount.
4. you can open as soon as possible but not later than the return filing date i.e. 31July.
5. Yes, you have to show proof of improvement when asked for. Interior decoration, floor addition, immovable furniture etc. can be claimed as improvement.
Please feel free to call/revert in case of any doubts
Thanks and Regards
Abhishek Dugar
CA CS B.Com