A combination of Dr. Newbie's "FakeDW" and my "Crime Spree On Any Difficulty" (Originally "Change Crime Spree Difficulty" by Ellie) mods. This grants you the option to play with any difficulty's filter on any difficulty in the game. Do you want to play Death Sentence with Overkill's Filter? Go for it. Or if you want to play on Normal with Death Sentence's filter, that's available too. Other notes:

• This makes Overdrill playable on any difficulty as long as the filter is on Mayhem+, loot value will scale depending on the actual difficulty the game is in and will NOT be inflated to the difficulty's filter. Additionally, you still have to complete the Easter Egg on Death Wish to get the achievement.

• The Secret will also be playable on any difficulty as long as the filter is on Overkill+, You still have to play on Overkill or above to get the achievement and you still need to become worthy.

This will NOT change available enemies, only map difficulty related elements that normally happen on that difficulty (Swat Turret spawns, titan cameras/safes, etc).

Credits: 
Dr. Newbie (FakeDW)
Ellie (Change Crime Spree Difficulty)