If my previous 4WD is anything to go by, then the harsh ride with highly inflated Bridgestones is the fault of their badly designed tyres.
I had similar Bridgestone H/T tyres on it and swapped them for Coopers A/T's. The ride and handling improved out of sight. It was amazing how much smoother it was even running the same pressures.
The Bridgestones also wore very badly with the higher pressures I was running to try and reduce their cornering "roll". Lesson learnt- Bridgestone H/T tyres suck..... I'll be glad when they wear out on my XL-7.