Playing with the idea of upgrading my front speakers...

I would go with the co-axils, since it would fit in the stock location... and you won't have to find a place to put the tweeters..

If you get the amp for it, you might want to consider getting rid of the rear speakers, since it will still be run with the CD player's built in amp (or run it together with the front speakers, or get a seperate amp for it and adjust the gain so it won't sound like the sound is coming from behind you).. Since when you turn it up, it might not sound to good since it will be underpowered...