Short Story:
A month ago ignition coil on Cyl #1 goes, I replace it.
Now a month later Cyl #4 ignition coil dies.

From what I understand about ignition coils, their isn't a need to replace them unless they are malfunctioning? However the shop is suggesting I replace the remaining 5 ignition coils.

Also as tempting as the cheap ignition coils are, sticking with OEM on them was is the best bet?

Oh here is my PPW for you:

 

I would go with OE or a good aftermarket.

The reasoning behind them suggesting that is generally with parts like this, if one goes the others aren't far behind as you're starting to find out.

You could do all the rest just as preventative maintenance or you can replace them as they go.

Depends on how much time you wanna spend working on it and how much cash you have in your pocket.

 

You can buy a whole set of used good and tested coilpacks on ebay for the same price as one new OEM from dealer or parts store. My car is right at 100k miles and has been fouling coilpacks due to oil from leaky valve gaskets. I've just been swapping in a good used one to correct the problem until I can get to the valve cover replacements.

 

Whatever you do, stick with the same brand on all 6 packs.