I have the Powerflex and we have pretty rubbish roads in the UK, well... in London anyway which is full of speed humps AND.... yeah they add slightly more stiffness. But the feel of the car in direction changing at any speed is totally worth it. I wouldn't go back to stock. I can live with a little stiffness but I would NOT do it if I had bigger than 19" wheels on.

__________________
BMW X5 E53 3.0 Diesel Sport | Sapphire Black Dakota Beige Leather interior | Year 2004

What I had updated
Carbon Effect Steering Wheel
Panoramic Sunroof Fix
PVC Replacement
All glowplugs and glowplug regulator
New discs and pads all round
All new front suspension links, bushes and rods