[EliozarCuellar]

I am in the process of buying a perma tune 911 model CD unit for my 1983 911SC. Pelican parts sells the unit for $ 535.00 it has the six pin connection at the bottom of the box. Other parts retailers sell the perma tune box for $ 435.00 --$ 455.00 with a pigtail six pin connection coming from the box . The Pelican box pictured in their catalog is silver. The other boxes are black. My questions are 1. Do the differences in the type of connection , and in the color of the boxes make one better than the other ? 2 Almost every article I've read states that the first suspect of ignition problems is the ignition coil the second is the CD unit . Coil failure can cause CD failure . Is this true? 3 If OEM unit doesn't make humming it has failed ?