I installed both sway bars on my
G70 AWD this week. I intended to do both at the same time, but I ran out of time after I did the rear on Thursday, so I finished the front today. I got to drive it with just the rear bar, then with both. Here's my impression - after installing the rear, I couldn't feel any difference when driving normally, but when I pushed it, it absolutely made a difference - I had could initiate a oversteer much easier with the throttle, which has been difficult with the PS4's in this heat.
The front bar is noticeable just driving normally. The steering feels more immediate and the suspension is stiffer - I think that may be the urethane bushings. I purposely drove on bad roads where one side of the road is worse and I don't notice any additional harshness - which I was worried about, since the roads are terrible around here.
The car simply corners better with the addition of the front bar. The weigh transfer is quicker, so it's easier to get set in a line, and then it feels like you're on rails.
This was the best money I've ever spent on a performance upgrade.