PlayStation support network has the information needed to replace and upgrade the harddrive depending on the PS3 model. See related link
PS3's have been designed to allow the harddrive to be replaced with standard notebook size harddrives. You can increase the size of the current harddrive or you can replace the PS3 with a new model with a larger harddrive.
No the PS3 has a harddrive to save
The PS3 slim has 2 models one with 120GB harddrive and the other with a 250GB harddrive
GB's refer to the size of the PS3 harddrive and factory produced models come with a game and a 320 GB harddrive for under $300
That is not something that you can do with a PS3. Discs are not uploaded into the harddrive of a PS3
You do not download the disc to harddrive you must purchase the game at the PlayStation store as a download to download the game to harddrive
Formatting your hard disk for the PS3 will erase everything on it. If you are adding a hard disk to your PS3 it will prepare the drive for the system.
No once updated it is permanent and I don't believe even a harddrive replacement can restore it. You also can put a smaller size harddrive in any PS3 and it will be the same model with a smaller harddrive and not a different model
PS3 has a Harddrive which you can change with a standard laptop harddrive
A PS3 harddrive is a standard size notebook harddrive and are only worth the amount of a used laptop harddrive of the same GB size. The $50 extra currently being charged for the 320 GB harddrive is about value of a new 160 GB harddrive so a used 120 GB harddrive would be worth much less.
It should be saved on your PS3's harddrive.
no you can not record the games that you play on the PS3 harddrive