I initially had the air lifts up at 20psi, with a couple of bikes on the rack, but this was a tad high as the steering was a bit too 'pointy'. This is just as you would expect from effectively increasing the rear spring rates, increasing the tendency to oversteer. Dropped it back to 15psi for the return journey and it seems just about perfect. The van is much more stable, no bottoming-out and it's generally much more pleasant to drive.
As others have said, this is possibly the best £100 you could spend on your van
