Vile Acceleration is more DPS then using Shred never fear of the -15% DMG, its not as much as you may think.

1 Forma are just here to make Exilus Mod work!

Exilus Disclaimer:
This is always optional but it can enhance the efficiency and experience of the Builds by a lot.
If you dont use ehm, you can usually get away with 1 Forma less!
There is many options that are benefitial - It is acutally worth it 90% of the time.