Black 130i here from BrisVegas.
Ditch the runflats obviously, CDV delete will ensure the car drives like a manual should. Big weak link of these cars is the suspension. I haven't modded mine yet but is next on the list (I've added the Quaife LSD which has been worthwhile especially for the track) before I do brakes and possible tune (only expecting a modest increase with a tune) and/or lighter wheels. Check out the Birds B1 suspension review that BMW Magazine did, there's some interesting insights into modern BMW chassis tuning. When I'm pushing on across poor road surfaces the rear end skips across and never settles.