iPod car docking

I've just ordered the new iPod 160GB Classic and I'm now looking for docking options. My hi-fi is simple as Cambridge Audio do a neat dock that's compatible with the amps remote but I'm stumped with the car option.
My existing MP3 head unit (Pioneer DEH-4700MPB) only has line-out and I'm troubled over the amount of poor feedback (on Amazon) regarding interference etc on even the better reviewed FM transmitting/charge kits and it leads me to ask 'is there a sensibly priced - less than 25 quid - wired FM kit available, the type that plugs into the aerial socket ?'. Alternatively, are their any suggestions? My gut feeling is to look for a dirt cheap secondhand head unit with line-in on eBay in preference to the transmitter option.

(I tried searching the forums here but can't find the search functionality)

Update:
I've just spotted theElectroSystems iDrive iPod MP3 FM Car Stereo Modulator (wired) on eBay for £20 - any thoughts? I'm waiting on a reply as to it's 160GB compatibility.

the iPod classic hasn't changed at all since the 80GB model apart from in storage size, so there shouldn't be any problems.

In fact, the only real reason the iPod touch is incompatible with some devices is because it's running the iPhone OS and cannot be used as a mass storage device.