Let's clarify here. You have 2 options.
One is to get a homebrew or an Extender, which are 29 wires, you would be able to either leave the mod in or use it to reflash the onboard tsop.
The second option is to get an LPC mod (OpenXBox/PC-Bioxx, X-ecuter, Matrix, or Aladdin). You would have to leave these in, though, since YOU CANNOT FLASH THE ONBOARD TSOP from an LPC mod.