Many have said a good steel nib is every bit as good as a gold nib. I think there's a lot of truth to that.
I'm a big fan of Sailor Pro Gear style pens, and have a 7 with gold nibs and another 5 with steel nibs, plus Lamy, Pelikan, and Kawecos with steel nibs.
The biggest difference tbh is in aesthetics, though the gold nibs a have a certain 'softness' they are also more finicky. With a steel nib, once it's tuned right, they just get the job done without worry.
Rather than getting a new nib, you might consider putting that towards a new pen with a gold nib. IME, I use the two types of pens differently, because of the worry free nature of steel nibs. The Sport is a pocket pen, steel serves it well.
If there are other performance reasons you're interested in a gold nib, then you might look at tuning the steel nib. Kawecos can have hard start issues, but a little work will turn it into an ink flow monster.