The lean is probably coming from how you hooked it up. Normally, the kit has a single crossover tube and single fill T’d into it. When the car goes into a corner the car has an action of rolling over to the outboard shock and compresses it. This higher air pressure travels through the hose over to the other shock and forces it to expand even further. Exactly opposite from what you want.
Get rid of the T and fill each spring individually or use a valve inline so you can fill both to the same pressure shut off the valve and this will isolate the springs from each other.
IIRC this works better, but still not the best. Low air pressures allow for a comfortable ride but also the low spring rate due to air compression still allows for a bit of a roll. This is why Grant advanced to the sway bar project.
You can find all this fun in the archives. Use the Search tool in the upper right of this forum page and use various key words until you find what you are looking for. You can also fine many other air shock experiences.
Note- the motorcycle spring/shock assemblies with remote reservoirs are not really “air springs”.
Disclaimer: The archives contain projects that are sometimes not for everyone. Depending on your skill set and what is in your toolbox use your best judgement and hide the children.
This is a link to Grant’s first front sway bar mod
https://community.electricforum.com/t/sway-bar/
Here is Grant’s Swaybar project on the rear of a 2016 Gem
https://community.electricforum.com/t/rear-sway-bar-2016
And the desire for true slot car handling Grant added a front Sway bar on his 2016.
https://community.electricforum.com/t/front-sway-bar-2016
But his summary on his project says it best-
“The car feels slower! It turns so flat and feels safe and just normal as you would expect in a Normal road going car you feel like you’re going slower LOL! Big difference super happy with the ride! I would not change anything.”