The BeSafe iZi Flex FIX i-Size has no carlist, since this is not required according UN R129-02 and there are hardly any limitations to use iZi Flex FIX i-Size in vehicles.
As mentioned in the user manual there can be a limitation in the highest position of the headrest when the seat is used in the rear vehicle seats at the side because of the low roof in some vehicles. In these situations the seat can’t be used to the total height of 150 cm. This can sometimes be the case for sporty vehicles but rarely for family cars. We recommend you to always try out a seat before purchase to see if it fits to your specific situation.
In some vehicles it might not be possible to use the SIP+ due to lack of space at the door side of the seat, then it’s fine to use the seat without SIP+.