It is not difficult just fiddly, you have to remove the centre consol , the glovebox and the lower drivers side dash and end pieces around the air vents. use spray contact glue and make Sure the Stitching lines up straight , following the lines on the trim , you want each piece to line up with the next one or it will look naff. I started with the centre consol but you can start anywhere .
It was my first time working with leather allthough i have covered a few subwoofer boxes in my time but they were all carpet or vinyl and didnt have white stitching to line up.
Leather is nice to work with tho,it Stretches quite well and if you get a piece on wrong you can peel it off and do it again... if you are fast.
I got a little creative with the top edges on the glovebox etc ,i cut strips of spare leather and used those to 'pad' out the edges, it looks better than just being flat imo
If i were doing it again i would cut out 'SRT ' or XF and lay those letters under the leather on the glovebox, , it be very cool .
Anyways take your time , dont expect to have it all done in a weekend ,slow an careful does it . spray contact adhesive, a chalk marker pen, a sharp knife , pair of sharp scissors and, a few of those chinese plastic trim removal tools they sell on febay. these are good for pushing the leather into place . a hairdryer and another pair of hands is a help too !
Go for it , it was actually fun and very rewarding too, people think it came that way ,thats cool with me.
Good luck and tell us how you go.