Technically any car seat will fit in any car, it all depends on how you use the car and how much space you are willing to give up for the desired restraint to fit.
The approx. rear facing depth of our restraints are 54-66cm, the final install depth would depend on the angle of the rear seat e.g. high angled rear seat = shorter rear facing depth, flat/low angled rear seat = longer rear facing depth. In some small cars this would totally take out anybody fitting in the front seat, other cars not so much and then it also depends on your usage. E.g I don't have adult passengers in my car often, if at all, so losing some or all of my front seat space is not an issue to my everyday use.
For forward facing depth is not too much of an issue as most restraints don't hang over the front edge of the vehicle seats, this may be different in vehicles with bench seats like a space cab/crew cab utes. But you do need to consider having space for the child's legs to fit between the restraint and the back of the front passenger seat.
Fitting more than 1 or 2 restraints in the back seat is a different kettle of fish and would depend on the ages of the children and the 'rear hip width' of the vehicle being used. For assistance when considering 3 across please contact our Customer Care Team.