Just curious if anyone has done a swap out of the stock steel nib that comes with the TWSBI Vac 700. I am considering getting one of those #6 Karas Titanium nibs from Goulet pens so I can a more responsive writing experience. They are listed on their site at $60. What are some other suggested options? Is it worth it to go with Gold for example. Love the filling system, ink capacity, design, and initial price.