Well don't know, i will have to chk the receipt for that & i don't know where i put it , tell you what search it in xbox faqs thread, it has been mentioned a no. of times in that thread i think..
Sorry, I don't know about the shops in Lahore & Islamabad, but if u come to Karachi, here r some shops from where to u can get PS3:
Bismillah Electronics, Karwan, Kamran & Electrodeals (from where I got PS3) and also Rohillas Electronics.
Buy the 80gb one for 31500 inspect it and if dsnt work or gives any problem give it back but most of us dnt need a warrantied PS3 cuz its not exactly the most unreliable console on the market and gives almost no problems so i guess u shud buy the 80GB one