xbox mod chips help

[goldenegg]

can somebody tell me the good mod chips and what they do (eg at www.norcalmods.com, they tell the name of the modchip and the also tell what it does)?

and on ebay i found this one modded xbox where you just have to put in the game, the xbox downloads the game to the HD, and you never have to put the disc in again cause its already in the HD, plus, the seller said that there are also no loading times cause its already in there. anybody know what im talking about?