I had the HP+ on my modified G35 and yes they did squeal alot on slow braking, for example, when stopping for a light. My solution was to coast to the light and brake with medium pressure. This provided minimum squeal and usually scared the passengers from waiting to brake so long.
As for brake dust ...... it's the price for high performance brake pads. Yes there was a extreme amount of dust! I plan upgrading the brake lines, brake fluid and HP+ brake pads. When the one piece stock rotors are done and beyond salvage, I'll replace them with a good 2-piece rotors.
I autocross at least twice a month, in the summer, and can't beat the HP+ for all around street/autocross brake pad performance. For the money, the
average street/autocross user will be impressed, except for the brake dust.
If I was to do high speed track racing, my recommendations would be different and probably suggest a different pad and BBk kit. More than likely, would have a race and street pad set and swap them out before each track day.