W 129 500SL iPod to Becker Mexico 2000

In my 500SL EZ 08/92 there is a beautiful radio in it. Sometimes there is great music out there. Sometimes I would really like to help with my iPhone. There is 1 iPod in it. On the radio of my other car is an Aux socket. When I hit my iPhone, my fine music comes out of the speakers. But the Becker Radio doesn’t have that. My son-in-law got me 1 FM transmitter. With that I can transfer some music from the iPhone. But to the One is the sound quality only suboptimal. On the other hand, the transmission is often disturbed during the ride. Now my question to the freaks in this enthralling circle: Is there an electronic trick to pair the old radio with the modern iPhone without going to the substance of the ancient radio? For all the many great advices I would like to thank you very much in advance…