Dear Brothers,
Its not about strong or nazuk back, Front Seats are atleast not that uncomfortable as people use to say, however rears are but for long travellings. Only thing they are bit hard and rear seats without head rest are also adding discomfort for long trips.
I have a WR, initially when I bought I have to do a lot to adjust the drivers seat to make me comfortable i.e. adjust forward and backwards, and then the angle of back in different steps as well and finally then I found the right place where I am comfortable now.
Afterwards, I have traveled twice from Lahore to Islamabad and back through motorway in a single day and I did not feel any discomfort to my back.
Please try to adjust your seating posture, may be it help.