The factory speakers
The factory speakers include a set of standard 5.25" paper cone speakers in the soundbar and a set of non-standard 4"x6" paper cone speakers in the dash. They make decent sound, especially in the mid-range, but they lack the ability to make decent bass or to make clear treble.

Fixing the problem
I jumped on eBay to see what was available and found that I could get a set of Infinity Reference 5002i 5.25" speakers for around $50. So I bid on a set and won then for $47 including shipping.

The install
The install was very straight forward. The speakers reused the factory mounting holes but the factory plug had to be cut off. I intended to reuse the factory speaker grills so that no one would know that I replaced the speakers but they would not work with the longer throw 5002i speakers. In the end, it probably took me about 20 minutes to complete the swap.

How they sound
I would have to say that they are a vast improvement over the originals in terms of clarity but the bass output did not increase as much as expected. On the negetive side, at higher volumes the 5002i speakers move a lot more and this causes some rattling and other odd sounds from the metal soundbar. In the end, I am happy with the new speakers.

What to do with the old speakers?
I have seen several adapter plates to allow the use of 5.25" front speakers in place of the stock non-standard 4"x6" speakers. So I thought I would make myself a set and try the old soundbar speakers in the front. I just happened to have an old computer case and after some time with a jigsaw, I had myself a set of adapters that worked great. Now that I have the old 5.25" speakers mounted in the dash, I would have to say that I almost like the old 4"x6" speakers better. Not that any of that matters because I plan on replacing them anyway. I will note one thing about using a bigger speaker in the dash, they move more and as a result they vibrate the dash and gas/brake/clutch pedals. This has made me lean towards the smaller 4"x6" plate speakers in the front.

What is next?
Next on my list is to replace the front speakers with some 4"x6" Infinity plate speakers and then look at adding a small sub.