Why do chassis have holes?
Similarly, can you drill holes in your chassis?
You may have difficulty in drilling round holes in thin metal. Most non-fitters do. But as the others said, don't go drilling the upper and lower surfaces of any chassis unless you know exactly what you are doing.
Then, what makes a good chassis?
A very large part of what makes a chassis good is also suspension geometry. It affects steering feel, anti-lift, anti-squat and roll center, among many other things. These are all very important when it comes to how a car feels dynamically. Low cars are AMAZINGLY better than high ones..
A chassis is the skeletal framework of a vehicle on which most of the mechanical parts like tires, axle assemblies, steering, brakes, and the engine are fastened. A vehicle frame, on the other hand, is the main structure of the chassis. All the other components, including the chassis, are fastened to the frame.