I've had Eibach on a couple of VW's we use to own and they make a solid product dude. Not much spring sag and they handle like a dream. Well worth the extra money they may cost.
Yeah, you'll notice a nice improvement with handling. May want to consider upgrading sway bars too. Might as well make er straighten the turns while you're at it.
Not sure. They make a good product too. Not sure why they'd be more then someone like Eibach or McGaughy's though.