Okay, so i am debating on getting a MSD Ignition for my car.... I know i need a Modified Cap, and a Blaster Coil..... But, then i see these boxes like the SCI or the other Red one...... What do they do? and do i need it? how much do all these parts cost? like how much does the cap, coil, sci or other box and all cost? and is it worth it?