In my experience of using off the shelf chips msd/ggr/ea, though it must be said ggr/msd are light years ahead of ea they tend to run richer, I dawdel a lot and found the plugs when using IK31 did not like it, the temperature at which the plug operates is crucial, they were not hot enough to burn off the natural deposits caused by burning fossil fuels(petrol), if I was driving harder no doubt they would have been better, my car used to run 3% co at idle to be happy, it now runs 0.97% CO(aftermarket ecu) so is not an issue, but when running the std ecu/shelf chips I changed to IK27 and this eliminated 99% of the problem as the plug runs hotter and is able to burn off the depsosits better and so not foul.
I usually don't go over 1500rpm for hour upon hour in the city traffic.
The IK27 will easily cope with what you have so would imo be a better choice.
tabetha