And Yes ShimmyMike. I am good enough to win races in wet weather, just get annoyed at the slowdown sometimes and how GP4's weather at certain races is miles from reality. Melbourne rain 4 times in a row!!!!!
I know what you mean daz! Im actually quite fast in the wet, espically round Silverstone and Spa, but it does cripple your computer. I tend to knock the res down a bit because I play at 1200x1024 and it runs OK.
Here is something to try. Turn sound accel right off in Windows, and crank GP4 to max res and detail and play Spa in the wet. From the TV cam is looks stunning!