In market section, one of each is on sale. Slim 250GB is for Mumbai only and superslim 12GB is from AP.
One can not mode Superslim. Though there is a mod available but risk of account getting banned on PSN is high. On the other hand if you are just looking to play on weekends and play more of exclusives, used games is way to go, IMO. They are affordable and range from ₹300-1200 depending on the title. Even if you sell them at half of buying price, you end up paying ₹3000 for 10 games (assuming average price is ₹600/game). This also would work out cheaper than downloading them and playing on a modded console - unless you have games available on local DC++ hub or with friends.