Coaxes are one little (trebley) speaker inside the bigger (bassier) speaker. They occupy the same size as the OEM (original) speakers and will give better performance. Naturally, th elittle one kinda gets in the way of the bigger one, so the next step is to move the trebley one outside the box, so to speak. That's component. Normally, you'll have your trebley ones pointing at yer lugholes, so they'll be higher up, too.
To connect 2 speaker drivers (either coax or component) you need something called a 'crossover'. They're often built in to the coax type speakers, and often seperate bits when you buy component speakers.
So, get coaxial ones and you'll not have to bodge anything (provided they're the same size of course!), get components and you'll probably have to fiddle more.
HTH
