I think the reason people have different results with the FM modulators is because of location. If your in a metro area with stations up and down the dial (wash DC) for example, you're gonna have bad results. Rural areas with fewer stations are usually best suited for an over air modulator.

That being said, it all comes down to how much your willing to spend. Obviously a HU with an AUX in for a ipod is gonna be your best bet as far as fidelity is concerned. Otherwise deal with a cheapo modulator, inline or otherwise. You have 2 choices. Pick one.

 

The JVC is probably less expensive than the Mitsu aux in and not a lot more than a modulator or aftermarket aux in. Alpine makes a pretty cool Ipod only radio with ipod as well, but no CD if that matters to you.

 

i thought that it was weird, i checked and double checked to make sure i had everything right but nothing i did made the signal come in any clearer. maybe i got a lemon fm modulater? i decided that i wanted to go double din but now the orbital kits are no where to be found

 

Last week, I bought and installed a Scosche FM Modulator for my 06 IX MR stock radio. It cost 25 bucks shipped and took about 30 mins max to hook up.
L-R phono with 3.5mm jack goes from the modulator to the ipod. Ground wire to chassis and fused power tapping into accessory circuit.
Sound is GREAT. Solid 8 out of 10, that's only because I know myself that it's modulator as opposed to CD. If someone sat in the car and didn't know - they would score higher.
Well worth it if u want to keep the car looking stock. Otherwise get a sexy head unit.