lows drop 20-30mm, superlows are 40-50mm apparently. So yeah. Go check out noss' car, he runs superlows on the front (or did, atleast.). They're pretty damn low though. The tyre will be just sitting inside the arch.
Springs help with the stiffness, but it'd be strongly suggested you change the struts. Didn't on my mates car and it was just all over the place...
Brand of struts depends on what you want it for. I know there's a few people around here using the monroes...