I believe that the less expensive versions of the RR Extreme Kart line are a non-homologated chassis, designed on a “global” scale for the World Formula / 4-cycle concept.
I know that Mac Minarelli had a (assumed to be identical, just re-badged with a different decal kit, given that RR builds karts for Mac Minarelli) kart that a few people in Canada were running with the LO206.
They’re a pretty basic kart, base components, aluminum wheels, etc., but there isn’t really anything wrong with that in 4-cycle. But they do have some adjustability, and yes, they do have a front torsion bar – I think most of the pictures in the ads are of a different Extreme Kart frame!
The kart could also probably be just fine with a Yamaha can or some other lower powered 2-cycle classes.
It wouldn’t be my chassis of choice if I was going TAG racing though.