Well, here are a few things you need to know. Did the dealer you got the kit from state that the 42's were required? If so that is likely what the chip is burned for. YOU NEED TO KNOW THIS. If you buy 42's and the chip was burned for 42's you will be ok. If you by 30's and the chip was burned for 42's you will have to get a new tune. If the chip was burned for stock injectors, you will need a new tune for either. Same thing goes for the MAF. The difference in price between 30's an 42's is not that much and you may end up cheaper with 42's if you don't have to pay for the retune. If you do not have access to a wideband this is critical information, so DO NOT assume anything. It is not likely that the chip is burned to stock injectors, since anyone selling superchargers should know that the stock injectors are not going to hold up over 300hp in a supercharged application. Also going with a larger injector than you need, will give you room to go, and will not hurt anything. Post back and let us know what you find out.