I can't speak to the F3, but I can speak for the 2010 and 2014 RT.
The 2010 without the RonBar was a pig, wallowing all over the road. The RonBar was an essential upgrade. ESSENTIAL.
In 2014 BRP seems to have figured out that they needed to upgrade the sway bar. Right out of the box, the handling of my 2014 RT was as good as the 2010 with the RonBar.
Nevertheless, at the time, I was riding mostly two up and decided to upgrade to a 2014 RonBar. It was a noticeable improvement, but not nearly as essential as the 2010 upgrade.
If I had continued to ride one up, I wouldn't have gotten the RonBar.
Now I'm back to one up, the RonBar is nice, but not essential.
I imagine the F3, experience may be similar.
Just my opinion, I could be wrong, and if I am, SOMEONE on this forum will be kind enough to let me know.