As said above, if you get a chance to hook up to a VCDS at the Festival you will get a definite answer as to which Coil pack is gone (if it is a coil pack?)
Replacing with the red coil packs, as others have said, seems to be pretty much just for show as far as I can see
I replaced my standard coils with the red ones and I have noticed no difference in performance improvement.
Just as a side note; if you are a stickler for part numbers, and original parts, it is worth noting that the red coils from awesome are "oem equivalent" and do not have Volkswagen/Audi part numbers stamped on them!
AKS tuning sell the coil packs with the original part numbers on them.
I ordered mine from Awesome before I realised they are "OEM equivalent" as opposed to full OEM.
I spoke to Awesome about it and they assured me that they are the identical coils from the same production line etc, etc. However, if I was doing it again I would order them from AKS
HTH
Dave