Happy to see another satisfied Nano owner here
For sure people who enter a nano with a note of sarcasism will be fully impressed by the car and get down with a surprise.
Do post some pictures on the mods done in the car.
About your question about aircon I would suggest you to scrap the idea because we do have only a very few examples of aftermarket aircons running niggle free.( Right from Old Ambys to present day cars..).