Losi XXX vs XXX, differences and what would be the best choice

[V12]

Today I meet two old friends who I raced with for a very long time.
All of us are somewhat semi retired ... at least for offroad. It means we all have raced offroad at some point but moved to onroad racing somewhere in the 1990s.

We have had Losi cars at some point and tried to discuss about them today ... well, who knows. The offroad bug may bite us again, for having fun when summer comes around.
What´s sure, 2WD only and have to be Losi.

Now, I personally did race a lot with the JRX2, Proformance mod, JRX Pro and some variants, but nothing newer. When the XX was released, I switched to onroad.
One of my friend did race the XX but no newer version. And don´t remember much ...
The other guy was more into Yokomo but might have interest into Losi now as well.

I know there was the XX, the XXX and some variants on them. But not any knowledge on them.
So those questions came up.
- what versions of the XX and XXX were released and what are the differences on them?
- which of these cars was the 'best' one? If there was the best and for which reasons.
- which versions could be found today?

It is not for any collecting purpose, just for having fun at the outdoor race track. And maybe joining a vintage race.