It would be a hit to his credibility if these kits he offers is nothing but gaskets. Maybe you should email him to see what is in the kit.
The pic shows what's in the kit and there isn't a worm and sector shaft, so his kit won't correct slop from wear in those parts.
Do Steer and Gear or Firm Feel replace the worm and sector shaft if they are worn? Just asking. If the problem is the output shaft bearings and the soft parts, the kit is probably all you need.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".