I too have an '04, and spent a good bit of time looking for the best replacement drop-in speakers. I tried the Pioneer 3-ways (don't have ready access to the exact part numer), but the stock speaker cover would not fit after installation. The inside of the speaker grill would have required shaving to make it fit. I didn't want to do this. I wanted speakers that would actually drop-in without any modification.
Everybody talks about the Eclipse speakers, and my biggest problem was finding anything out about them. The model numbers mentioned on most all documents and threads in this system reference outdated models that are no longer available. Also, finding a dealer in my area where I could look and listen to them proved unsuccessful. I get the impression that these speakers are not even marked in the US, but maybe they have them someplace.
On eBay, I found one, repeat ONE, listing for the Eclipse 8363 speaker. It is a very good sounding 3-way speaker (hard to find 3-ways that drop in for our car!). It is a true drop in (at least for the 04). They sounded a good bit better than the Pioneer 3-ways (which didn't fit due to grill cover). Installation takes a very small number of mintues and is perfectly clean (All you need is a phillips and flat-head screwdriver). Although they are not 100W extremely high-end speakers, they aren't cheap either. I was very impressed by them. I purchased one set off a guy on eBay to try them out, was very satisfied, and then placed a second order and bought a second set for the rear.
Also, without the services of a detective, it's pretty darn difficult to even find Eclipse's web site. Here it is:
http://www.eclipse-web.com/
I purchased 2 packages of wiring adapters from Circuit City online. They offer free shipping on them. Each package contains 2 adapters. Honda's have an odd wiring connection to their speakers, and you can't simply remove them and plug the car wiring to new speakers. These adapters allow a simple and clean installation. Here is where you can find the adapters (you can probably pick them up at your local Circity City, but I think they charge a couple extra bucks for them):
http://www.circuitcity.com/ssm/Metra-Sp ... tDetail.do
I just checked on eBay, and there are no Eclipse 8363 speakers up for sale. Here is the link to the closed auction where I purchased them. The guy selling them seems to put up one at a time, and sells them using "buy it now". Keep an eye on it, and I am sure you will see them in a day or so:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... RK:MEWN:IT
I have noticed other used and even other new Eclipse 8363's on ebay. The new ones are commonly from a guy who happens to have a single set in his posession. If it helps, keep in mind the guy I bought them from seems to have an endless supply and is not just trying to unload something he picked up somewhere. My experience was very good with this seller ... the boxes were brand new, all paperwork was in the box, screws, wires, etc. were as you would expect. (of course, I didn't need the screws and wires, but it was one more clear indication they were new)
Important Note: In fact, the speakers I received were brand new. However, as is common when authorized dealers sell surplus product to gray market resellers such as those on eBay, they hide the original source of the items by removing serial numbers. The packages have been opened, and serial number stickers removed from the speakers. I took a chance, and was satisfied ... even purchasing a second set. Speakers won't go bad unless you purposely blow them out. I suspect warranty coverage would be difficult, but probably unnecessary.
Hope this might give you some ideas! Good Luck!