I've seen in a lot of races people asking for setups. Can you send setups to other people from inside the game? How do you send/receive them?

press "N" until the connection list in bottom right comes up.
then just press "SS" beside the name of the racer u want to send the set.
if u have recieved a setup there will be a green "S" beside ur name, click it, name it and it will saved and u can choose it when u go into the pits.

Brilliant, thanks

I always wondered what those were for

but don't ask me for one while I'm racing. I find that incredibly annoying.

i would agree - don't spam people whilst they race. take a note of who's setup you might want to try and ask them specifically AFTER the race has finished...

on the 'N' screen if you click the persons name it will send a messege to that person directly. i have found that if you just go on a server a say 'setup please' to everyone, hardly anyone will send you a set, one ot two maybe and they are normally the slower guys...... that said if you ask a specific person nicely AFTER the race has finished as long as it is not a 'team event' setup you will more than likely be sent it

Well, yes it pays to be polite.