Here's a very handy app that automates the pit stop process, according to presets that you configure.
http://xgn.com.au/index.php?topic=1234.0The app makes it so that as soon as you stop in the pits, it automatically does all the mouse clicking to select tyres, fuel and repairs, so your stop starts straight away.
With all the pit stops in S10, you'd be best off trying this app out. Remember, you can only pit in an online Race session, so jump on the practice server and try it out.