Well that price is surprisingly low. I would suggest you check the market price and see what's the price of an Exi and Vti. And then see if it makes sense to go with the Lxi.
The cost of upgrading it with used parts (not new) would probably be 30,000. But then you could also get a bulk discount. Just listing some prices off the top of my head from Lahore.
Power steering pump 3000
Power steering rack 7000-10000
Power windows 2000 each x 4=8000
Central locking 1500 each x 4=6000
Power mirrors probably 3000 for the whole set
I'm not really sure about the price of power windows and power mirrors but the rest are pretty accurate.