B5.5 Aux in

[nightshade]

Hi chaps,

I've just collected a B5.5 to replace my written off B5.5 (Rip old buddy)
New one is a highline with the usual 6cd and gamma in the dash. I'm perfectly happy with it, save for the lack of being able to connect my MP3 player. What's my best option for this?

I've looked at FM transmitters, but worried they might be kak sound quality
I don't want a tape adapter

I could fit my old single din Pioneer with has a usb slot and an aux in, but I think I'd lose the 6 cd changer as I don't think it will talk to the Pioneer.
Or I could replace the whole lot with a lovely double din unit with gps and all sorts, except I don't have the cash for that sort of thing right now.

I've seen posts online of people soldering something switchable between the changer and the HU, but that's probably beyond my soldering skills.

Is there another options I've missed? What's the best solution?

Thanks