There are only two R18's in the game, and one is the Anniversary Edition.
Also, you should use a better thread title than just 'tune'. I don't know if you're asking for a tune, posting a tune, or asking about tuning. If anything, ask some of the tuners.
I'm not too great with LMP cars, but I would have taken my 15th Anni out and tryed to get something better than stock to help you out.