Update.
The car crossed over 20,000km recently and has been in my possession for 11 months now (bought as a Sep 2017 demo in Jan 2018 with under 50km on clock).
Some key points, based on my earlier posts:
-Lack of lumbar support is not a real issue, after tweaking the angle of the seat to point upwards.
-Overall fuel consumption on Fuelly.com is as per my signature below.
-My bespoke spare wheel support is pretty neat and secure but it does rob space in the boot.
-My OEM M3 vinyl decals and the non OEM boot spoiler are holding up well, but I do get mixed stares in my office car park.
-I want to do more cosmetic mods, but I am reserving those for an upcoming (cheapish) weekend toy.