Help with my Posion blade vortex, exploding chest

I followed this video:
https://www.youtube.com/watch?v=YLEoOe18-dU

So now I have a poison blade vortex and I saved a couple of exalts. I am thinking about going for an exploding chest, but they are really expensive. Will it even help? Now I have 20+20 % chance of explode on my two weapons with 25 % of hp in chaos dmg. The explode on chest is only 3 % damage. But it seems to be a good peice in the build. I don't want to buy something for like 7 Ex and then not use it. My most expensive gear peice now is like 30C.

Any tips? It is my character "Shassin" on Heist.