With a DSM, you dont want to bother with "chips"... We have far better options. But, a common chip upgrade is the TMO chip. Now, its not the "chip" that all the ricer put in to add 3.7 HP. In fact, its not there to add power at all. So why does everyone run it? Check out the website.
www.tmo.com. I believe they fell right off the face of the earth, but there are a couple knockoffs on ebay that are very similar, practically copies. Some have even more features. The one by Jeff Oberhiezterlistergajksds is known to be good.... The catch is, and this applies to 1g or 2g, you need an EPROM ECU to be able to use it, and you need to get it "socketed" so you can replace the stock EPROM with the new one.
To add power, DSMers typically tune with fuel tuning devices such as the SAFC, or DSMlink for 2Gs (.com), MAF Translator (
www.fullthrottlespeed.com), etc. Use a datalogger so you know what to do with the tuning device. This is what makes DSMs special

Forget about "chips" in the traditional sense of the word if you own a DSM...