Hi guys, firstly I am sorry to recycle questions which have probably been asked multiple times, but the forum search requires a lot of digging about sometimes!

Regarding air filters - If I fit a DNA stage 2 filter do I also need to keep the stage 1 filter in (and replace with a K&N/DNA) or does the stage 2 acting as a primary filter mean the internal filter is not needed? I'm also assuming that the snorkel is to be removed as well.

Also it's to my understanding that to run with modified filters it's advised to use Kev mod (I am on an 04' XT), would I also need to make adjustments to the CO settings?

Sorry for the age old questions guys.

Thanks.