Lots of ways to do this with hubs, thinner hex and such. Narrow track width can improve handling characteristics. Mainly more side bite in the corner. Makes overall grip increase or feel like it has, especially on tight indoor tracks. Keep in mind that it makes the car harder to drive and not as forgiving. Might even traction roll. I don't feel it is needed for most tracks, but you are the only one who can test it to confirm its right for you and your track. Test it and share your findings with us here.