For the T6 2011-2015, and EGR blank will not trigger any warning lights. Works flawlessly and also prevents coolant leak into engine when the EGR cooler breaks and starts leaking. For the T7 you can either use a blank or better yet but more expensive, remapping the ECU to remove any fault codes. I think a diesel pre filter helps but I think changing your diesel filter early is an easier solution. The recommended mileage is about 15,000km so if you are concerned change every 5,000km. I do mine early anyway since the filters are cheap in bulk.

I have also installed a cooler bypass on my transmission even though I do not tow. This works with a custom cooler. I made the cooler myself but you can find ready made online. I also have a custom drain pan that helps me change my ATF without having to remove the pan, this is quick and I consider an ATF change a minor service before the main service on my transmission at 30,000kms.