I haven't performed these mods yet, but I thought I'd share the links.
The first two mods are to reduce the play on the steering wheel
The gist of this one is that you extend/replace the metal rod that supports the plastic spindle
The dimensions for the rod to support spindle are in the video
The gist of this one is to replace the plastic bearing with something along of this

from:
http://www.vxb.com/page/bearings/PROD/Kit7440*I should add that I have seen a few different dimensions and its recommended to grind a bit of the spindle down. I saw someone report freezing the spindle so that it would shrink, then pressing the bearing onto it. This particular mod is not without some work...
A popularly referenced guide.The other mod which I don't have a link for involves hacking an emergency handbrake to the wheel for drifting
Another popular mod would be reversing the foot pedals.
If anyone has anything to add, or share some success stories, please do.