have a look to the pitstop dialog here: http://isiforums.net/f/showthread.php/3907-Dialog-with-race-eng-example the script can easily be adapted ("change front tyres" or "change rear tyres")
His request is about beeing able to select tyres in garage for each "corner" (LF/RF/RL/RR) rather than just "front"/"rear".
+1 on it. In addition, it would be nice to "inspect" each tire after a practise run. Once there's visual tire damage I reckon that wouldn't be difficult to implement.