You can always mess up a softmod. If you delete some dashboard relevant files on your harddisk, your xbox will boot in an error screen. The only option to fix this behavour is connecting the harddisk to a pc ide port, unlocking it and fixing it's file structure. A chip modded and Tsop flashed xbox can boot from a dvd, even with a blanc harddisk in the xbox. That are the biggest differences. You can alter a chip bios so that the xbox startup screen changes. You can change the color, disable the sound and that sort of stuff.
You will need dashboard 5960 as initial dashboard for the softmod. If you have a recent game with online play features, and you have your xbox connected to the internet, the game might update your dashboard automatically if you select it's online features.
The most recent softmod is indeed the ndure. You have the kingroach ndure 3.1 which works in combination with xboxhdm, and you hav the Krazy ndure which works with a game exploit.
You will find 3 main groups of modding.
1. Installing a modchip
2. Using a game exploit
3. Using xboxhdm and a pc
1. You will need a modchip
2. You will need one of the exploitable games and a way to transfer the gamesave to your xbox. A while ago, the action replay set was the way to do this. Now, you can use a compatible USB stick and a gameport to USB cable. The xplorer360 pc program allows to write to a fatx formatted partition.
3. The cheapest way to softmod your xbox with xboxhdm is the hotswap. This method can however damage your xbox, your hardisk, and your pc. Some guys here will claim this is not true and say that it's a perfectly safe method.
I prefer the eeprom reader method. You need a little homebrew interface to read out the xbox eeprom contents. It can always be used, even when the hotswap is no longer possible. If you do everything as expected, it is perfectly safe for your xbox.
http://forums.afterdawn.com/thread_view.cfm/357863 You can buy dvd rom's that can be flashed with a special firmware. That firmware together with some special program allows the readout of original xbox and xbox360 games. So, it's no longer true that you can only backup your original games with the xbox.
regards.