MarkD sells a 93 octane chip. You aren't going to find any freebies out there that will be as good or better than that. It is my understanding that the M42's stock ignition timing is very conservative and that a lot of the gains found in performance chips are from advancing it in certain parts of the power band. Again though, I don't think that any quality tuned M42 BINs are floating around for free.
Also, street racing isn't a good idea. First, you will probably lose the $40 since there are plenty of Civics out there that can smoke a stockish 318iS. Second, you may lose a lot more than $40 if you get caught. I've seen way too many bad things happen to friends and people on other car forums as a result of "friendly races" in the 13 years I have been in the car scene. Be careful and keep it under 60MPH. Honda's are actually very respectable cars, although it can be hard to take them seriously with the insect-looking body kits that people put on them lol.