yep, when you go to "oil change" you can see the color of the oil.... my personal policy on GT is to change it every 6 or 7 races, regardless of color... it helps.... and if you buy a Used car, changing oil gives a significant performance benefit
Oh and by the way, washing the car from time to time actually gives a performance benefit, chiefly in top speed, I found out that after a car wash, there is a bit of an increase in speed, especially on the faster tracks....
Amazing that they've thought of all this huh? I cant wait to see what GT5 is gonna be like , unfortunately, might have to save up for PS3 before that...