Hooking iPod to stock head unit

I have a customer who was asking me if there is a way to hook his iPod to this head unit and not sacrifice sound quality. I know they make some FM Modulator adaptors but as most of us know – if you live in the city or even in general anything that goes through a FM Modulator’s ends up sounding poor. He also said he needs to keep his stock deck because the car is a lease so getting an Alpine is out of the question. I guess what I am looking for is something that will have the quality of alpine but work with the stock deck Anyone got any ideas?

I ended up getting an adapter from www.mp3yourcar.com Install was cake 1 plug, has good sound quality, and they got it to me fast.