Ya’ll need max casting speed for invasions?

I’m working on a RL200 Mage/Occult build and I’m debating getting 40 DEX (+30 w/ Radagon Icon)z My stats are already spread pretty thin as I’m juggling INT/FTH/ARC… that being said I haven’t ever invaded without having max cast speed and I’m wondering if it’s worth it to sacrifice some AR…

Thoughts?