Often, the new guys to racing will get frustrated when they are a few seconds off the Leaders. The temptation is to make their cars faster and lighter to make up those seconds. This often leads to an even bigger gap
If you're new, start off with the kit setup and get the tires that the local guys are using. Find a good, "middle of the road" gear ratio for your car. If you're new and having to add a fan to keep motor temps down, you're geared too high. With this setup, start driving the car and make minor changes to get the car tuned in. Don't ask the locals to do it for you, but ask 'em questions..."My back end is loose out of the turns, would laying the shocks down help?" Don't worry about making your car faster until you are consistently taking clean lines and staying off the boards.
A well setup "slow" car in the hands of an good, experienced driver is going to be way faster than any "fast" car that is bouncing off the boards, taking wide turns or spinning out in the corners.