Battery Vehicle Society

I'm new to all this & notice there's not much info on here re the Aixam. I was wondering how similar the construction of the 500cc diesel car is to the electric ones? I understand they are built on an aluminium frame with plastic body, are the frames the same for the 2 vehicles?

Is there any crash rating info available for these vehicles (seem to remember quadricycles aren't crash tested???)

I've seen a bit of talk on here about poor battery life on these - how easy is it to swap to a differnt type of batteries - something like Thundersky or Calb perhaps? & what are likely costs to match or beat the standard battery capacity?