We have seen info and posts on features available on the M2 CS which ain't available on the M2 Competition.
Here's what springs to mind about the opposite: available on the M2 Competition, but unavailable on the M2 CS:
- 'Long Beach Blue Metallic' and 'Sunset Orange Metallic' body colors
- blue-colored or silver-colored brake calipers (the blue-colored ones allow 18" wheels too)
- 19" 788M wheels (silver or darkened silver 'black') or 19" 437M wheels (darkened silver 'black')
- Comfort Access
- Driving Assistant - 'Lane Departure Warning'
- Driving Assistant - 'Collision & Pedestrian Warning'
- dry carbon trim
- heated steering wheel (leather)
- driver's knee pad
- regular two-piece seats with thigh extension without cut-outs or one-piece sport seats without cut-outs
- Dakota leather
- 'Polar Blue' or 'Kyalami Orange' contrast-stitching
- lumbar support
- retractable armrest (center console)
- storage cubbyhole under the armrest (center console)
- wireless charging & WiFi hotspot (center console)
- maintenance-friendly trim for center console surface (spilling, wear & tear)
- additional USB slot (2.1 Ampère) inside the cupholders space
- additional 12V-socket in the rear (rear part of the center console)
- airco ventilation in the rear (rear part of the center console)
- 40/20/40 foldable rear seats
- armrest in rear seats featuring open/close cupholders
- load-through in rear seats
- non-adaptive ('passive') suspension ('one size fits all' uniformity)
- metal roof in body color
- roof rack anchorage points (roof drip rail with flaps)
- glass sliding roof (moonroof)
- no front splitter lowering the front bumper (bumps and angles ground clearance)
- side mirror covers in body color
- small Gurney flap on the boot
- darkened exhaust tips
- angular cut design for the exhaust tips
- bonnet without powerdome & air vent (no engine bay 'direct access/ingress' for objects and humidity)
- no add-on fender extensions
- black M2 badge on the boot