Belkin TuneFM for iPod

Another option is to install an amp under the passenger seat or in the trunk. Get an A/B RCA splitter and keep it in the glove compartment or any convenient place. Run the stock head unit to the splitter. Run the Ipod with rca cables to the splitter. Then run rca outs to the amp. The amp will drive your speakers more efficiently and both the head unit and the ipod will sound better. I do this on my Accord and I'm very happy. I even upgraded the speakers to really bring out the sound. You can do this yourself or have an auto stereo professional install it. If you want to use your iPod a lot in the car it's a great investment. And thieves only see the stock head unit so it's not a theft magnet.

there is a factory amplifier in the trunk in my car. The car has a very good sounding Mark Levinson Lexus system. Really don't want to screw around with it.

I won't belabor the point any longer. I just know that running the ipod with rca's to an auxillary-in in the head unit, directly to the amp through an auxillary-in, or with a splitter between head unit and amp, will sound much better than an fm transmitter or even a cassette adaptor.

You might check and see if there is an aux in available for your head unit from the dealer. I bought one for my BMW 3 Series, and installed it myself--I think it was a whopping $15 or so. Its tucked up under the dash neatly. I also bought a cigarette lighter USB adapter, and a USB charger, and wired that into the fusebox, added a promount to slide the iPod into, and have an iPod install that looks virtually factory.