Run the cables up the driver's side-avoid proximity to any power cables. You'll need to remove your rear seat to get the antenna & DIN cables from the trunk into the passenger compartment. Rear cushion pivots up when you depress the 2 red tabs; the seatback is held by 3 small 8 or 10mm bolts.

With the seat out, you'll see the opening between the trunk and passenger compartment, through which you can run the cables.

Next, you need to pry up the door sill trim pieces, and remove the trim at the bottom of the interior "B" pillar (remove the 2 phillips screws, then while holding the interior trim through which the front seatbelt is threaded, pull the lower trim piece down and away...this will gain you access under the carpet.

Now you're as far as the kick panel on the driver's side. There's a phillips screw that was exposed when you removed the driver's door sill; remove it. Now simply pivot the kick panel rearward and remove it. That done, you'll need to remove the trim panel under the instrument cluster...if you snake the cables above this piece, it'll get you to the center console where the radio is.

Hope this helps.

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo