When I hear the word "stage" when it comes to engines RICE comes to mind.
Rice Stage 1: Altezza lights, fart can, blue headlights, cut/lowering springs on stock rims..
Rice Stage 2: Big Wing, carbon fiber hood, fog lamps, wheels stickers.
Rice Stage 3: Body kit not painted.
Rice Stage 4: Paint job.
Rice Stage 5: Any stacking or exageration of any of the above parts.