I used the Ultimate compound pads with the STi 4-pots on my GC which also saw high-speed, auto-x, and rally-x work. They worked fantastic with the cyro-treated Powerslots but they dusted like mad. I never really cared much how the car looked as long as everything functioned well. Function > form.
They are very dusty. I had them on my StopTech BBK on my WRX and was constantly cleaning my rims. I can't compare the braking performance because those were the only pads I had with the BBK. Although the BBK with 332mm rotors was FANTASTIC.
Oh I just needed street pads. I'm not going to go do any serious track racing. I guess I can deal with the dust.