If your car is BRAND NEW, maybe your pads havn't worn to the shape of your rotors yet? or maybe when one (or more) of the pads was installed, something got wedged between the pad and caliper, creating uneven wear?
I got SD IS300, and brake feels really weak at the beginning. I've test drove all the yr of IS including 03 and I have to say that it is totally different. It feels like it's weak when you tap on the break but it gets harder compare to other IS's when you full break. hehe don't worry, you are not the only one who noticed that:-D