Hilux, Surf, Fortuner, etc. all are generally known as Truck Family
They are rough & tough but never comfortable.
This question has been asked many times on forums and in whatsapp groups. And most of the time people say Sell it and buy something else 
The ironman suspension is very expensive. Not only shock absorbers, but you have to change few other things too. But again it will take like 3-7 laks to upgrade its suspension but at the end the results will be unsatisfying again because these machines are rough & tough by nature.
BTW, I saw trucks in USA like Ford, Dodge, Chevvy, etc. and their 2015 onwards models are quite comfortable.