Just finished fitting a Clarion CX501E with steering controls following MR Gav's help and advice.
MR GAV
It is fiddly to get all the wires behind it but a bit of perseverence pays off.
Had to install it twice as I didn't check that the permanent live and ignition live wires (Red and Yellow) are reversed on the new head units (kept losing radio station presets) and although the connector leads are for a vauxhall they were still in the wrong order.
Stereo connects to iPhone 5s and makes handfree calls through the stereo with crystal clear reception.
Only thing to note is that having a big dial in the centre means not a lot of room behind the gear stick if you have an automatic when you push it back into Park.
I chose a black fascia surround as the grey one was more metallic, lighter grey and with the inner black fascia for the stereo i thought it would be too many different colours. You'll also need a DIN aerial connector.