This is a common issue with earlier model RX8's caused by condensation. The engine injects oil normally, so this may be why the oil level is low, and condensation may cause it to be milky. Many RX8 owners have witnessed the same problem, especially in cooler weather.
Here is the TSB for this issue with Mazda's remedy for it.
http://www.finishlineperformance.com...50-06-1664.pdf