You can get some monster clouds out of the set up you already have....though I personally think the .2 ohm tri coils are better then the quad coil head. They also have a Clapton coil head coming out, would be worth trying.
If you absolutely need more then what the tfv4 can put out, you are going to be looking at RDA's and building your own coils.
Sent with one hand, the other is busy vaping