Can I extend the esc leads that go to the motor ?

If I need to can I extend the esc leads that go to the motor or is this not reccomended? Also I have a MGM 160 controller going in my revo, where are you guys mounting them, should the controller be mounted on the thinner side so that the heatsinks are both exposed or can I mount it with one of the heatsinks facing down?Also what size connectors should I use to connect it 3.5mm or 4mm ? Also are there any special soldering tips to for bullet connectors ...never soldered any before...thanks