I have the dunlop sp900 tires on my IS300 and they are noisy. Of all the tires recommended by lexus for this car which are the quietest.

 

My sister has an 02 IS 300 Sportcross; the car didn't come aligned correctly and the Bridgestone tires wore out fast and became noisy as they wore. My sister bangs the car into curbs, knocking the car out of alignment. The next tires (Falken) became feathered and were very noisy after about 10k miles. Currently the car has the Michelin Peralto tires. Very nice tires. We'll see how they do after 10k miles.

Were the Dunlop tires noisy from the beginning or did they become noisy after about 10k miles? When you replace the tires, make sure to get the car correctly aligned. The car is never going to be luxury car quiet. Also, the low profile tires are never going to last you all that long, and will get noiser as they wear. If you want long tread life and quiet tires, you have to put on the 16 inch rims with a touring tire (like a Michelin MXV4, Bridgestone Turanza, or Continental PremierContact tire). Of course, you would then sacrifice the super sharp handling.

Search the reviews at www.tirerack.com for lots of opinions from owners of different tires.
Good luck.

 

They started off noisy and got noisier after 10k miles ive heard the bridgestone potenza are supposed to be really quiet.

 

If you have 900's there a little more agressive than the 9000's which make more road noise. If you have 9000's its just the typical noise because they are thin and low pro's... All tires are going to make that noise to so extent but I know that the 9000's are one of the quietest if not the quietest..