Diamond Difficulty by Kami-sama_FR

Fight one of the hardest games of your N7 career and hope your team can survive the onslaught of ferocious enemies that will pin you down.
Diamond Difficulty contains a very large set of changes that raise the stakes of going solo. Enemies have more health, do more damage, and work together to lock you down. Constructing a team that has effective communication and spatial awareness is a must. For successfully completing this challenge you're rewarded with an extra hundred thousand credits over platinum.
Downloading Diamond Difficulty Mod
Open Mod Manager and select Tools > Enter ME3Tweaks ModMaker code.

Enter the following code: 302

The mod will now compile and be ready for use in about a minute.