From reading the board I noticed the the wires from the LC-1 are somewhat short?

Can I extend any of the wire from the LC-1 using any regular 18G wire from the auto parts store?
In addition, If I where to wire all the wires to the engine block, I would like to bring a wire from the engine bay into the cabin behind the firewall and use some sort of connecting block to connect my wires. like this - or some fort of plug... thing of a USB port used only for ground..




So my questions are

1)if I need to extend my wires what gauge can I use (18G ok?) and how long can I extend

2)can I use a plug to solder all the ground together and connect them to a wire that goes to the engine bay.

3)What think does the engine bay ground wire need to be?