Hi,
I did the aux in option. Got a cable of ebay with the correct plug in pin plug on the end and a female 3.5mm jack on the other. The air vents come out with gentle persuasion and two flat head screwdrivers then the stereo is a couple of screws and its out. i ran the cable inside and put the female aux in jack inside the ashtray, actually the small bit on the right that you are supposed to put the cigarettes out in first as the lead fits a treat in there.
pretty simple, took about an hour and cost approx £15.
itchyfeet.