I think that's the same stuff in my IS300 (Lexus calls it Ecsaine, but it's just their branded Ultrasuede).
The manufacturer recommends a damp cloth, but if you must use a detergent use a little bit of Woolite with some warm water. Brush gently with a soft brush - I've seen some people ruin Ultrasuede with Carpet Cleaners and stiff bristles.
I had to do a set of Recaro racing seats.. 100% Suede. A real stiff brush (like CMA's vinyl and leather brush) used GENTLY to pull up the nap, and a spray bottle mixed around 48-64:1 detergent to water. I used a micro drop of QEW and water. It took out a small stain, and lifted the nap to a real new clean look. The key as mentioned is dry!! suede doesn't like to get wet, so you want to use very very very little water, and towel dry immediatly.
One thing i suggest is prevent before anything stains. They sell Suede protector at leather stores. i would pick up a few cans and protect it ahead of time.
