ok after you have read and written the nand you can completley remove the nand x kit BUT you have to leave the jtag connections installed
i would really suggest using the quick solder boards then that way if you ever need to mess with the nand its a simple connector instead of having to re install and solder
Xecuters guide here has everything marked up for you just remove the NAND connectors if you never going to use the nand x on the xbox again
http://www.team-xecuter.com/forums/showthread.php?t=54423
3 connection types i reccomend the quick solder boards
1. using quick solder boards (probably the easiest option as you can just clip the wires to the boards and they stay in forever when you have flashed you just unclip the wires
2. using the pin headers is also a good option kind of the same as above
3. using straight wires you will have to remove them after you flash the nand and if you ever need to come back you have to re solder