I'd there a secret aux input begins the dash?
 

I was wondering if anyone had pulled their stock EX head unit out and noticed if there's is a place that could be used for an mp3 input? I still can't wrap my head around the fact that it's not on the dash. This made me question if the unit was possibly implemented in a way that Honda chose not to use it, kind of like rca plugs on an after market head unit.

Nope, the closest you can get would be to inject a FM signal into the antenna input.

Is it possible to splice an fm transmitter into the antenna? I hate the hissing I get with the Zune. I did splice a wire on the transmitter cable increase signal strength that can usually overrule an fm station for my car, but I still get static and it's worse when the display is illuminated. Although, my antenna in my current car sucks, I can get or two stations of static. It used to be great once upon a time.

This is the only reason I don't want an EX, it's a complete downgrade in versatility.

Wired FM modulators which you place inline exist. You just plug the antenna cable into the modulator, and the modulator into the antenna plug on the radio. As a bonus most of them will disconnect the antenna when an input is detected so you don't have to worry about a local radio channel being on the same frequency.

I had one for my satellite radio receiver in my old civic and it worked great. Assuming the EX has a standard antenna plug in the radio it should work fine.

EX does not have a standard antenna plug. you will need the HD31 adapter from TSS radio.

I did this in my EX a few weeks ago. currently, it is the only option to add sirius at this time.

How is the sound quality?

from an audiophile viewpoint, it is not as good as my other cars, which have an aux input. some of the highs/lows are not as dramatic and the sound is not as "rich".

from a commuter standpoint, it is just fine.

I suppose I'll have to go the way of the flash drive. I've read that 3mu files don't work. But I did read a post over on the Chevy Volt forum that the problem they had was the file was trying to link to absolute file paths instead of relative. I wonder if this might work on the Fit.

To be fair a lot of that could just be Sirius itself. The times I have listened to it, both in cars with built-in receivers and with aftermarket, the audio quality has been sub-par at best due to the insane amounts of compression they use on the satellite feed.

Some of the comedy channels were barely cell phone voice conversation quality.

not in my experience. in my s2000, when i used the fm modulator, then changed to directly wired into the headunit, there was a noticeable difference in sound quality and volume.