Thanks....as you can see, the Pentax K-5 is perfect for this conditions. Here two 100% crops of the first two pictures. These crops are unmodified (only contrast changed). Oh and also I shoot jpgs when shooting motorsports because I don't want to process the pictures and the results are completely usable and even printable on the newspaper (as some of my motorsports pictures have been printed on the sports section).
First picture, 100% crop, ISO 800, 1/500, F6.3, DA* 16-50.
Second picture, 100% crop, ISO 800, 1/640, F6.3, DA* 16-50