Already enquired about that. From what I have read and also asking Afrishocks the B16 does not require any modification and is a simple fit. I am actually in 2 minds if I am going to go performance parts suspension or Bilstein (B16 with active ride height). Interestingly enough I have been doing some research on the performance suspension, firstly it is 10mm lower than your standard M suspension it is 25% stiffer and has 10% less travel. You can definetly expect a harder ride especially if you are considering 19" rims. Taking all of this into consideration the B16 ride height is looking more attractive as you can switch between Sport and Comfort (similar to the M3 EDC but more aggressive), the only problem I have is justifying a R32,000.00 (Afrishocks quotation + installation) cost when you can aquire the suspension for around $2200 online here.
I have already purchased a pair of Dimisa tips, CF M-tech diffuser, M3 lip and matte grill for my 335. I personally am not a fan of the performance shortshifter, it is way too small and actually looks quite cheap in real life. Since you are in JHB you should ask your dealer when they are getting that performance 135 that BMW SA has floating around going from dealer to dealer. You will see exactly what I mean by the short shifter.
I am hopefully going to be getting an answer next week Tuesday on the performance brakes for the 335. I just think those yellow callipers on a sparkling graphite coupe will look SICK. I have already told BMW that if they cannot provide me with better brakes I will then fit Brembo and it is their problem to make sure my MP holds.
I would not touch the exhaust system here in South Africa if I was you. I can tell you right now your MP will go straight out the window. Maybe look into the performance exhaust system that is available for the 335. I would have considered them if the tips were not so crap and I could have put a set of Dimisa tips over them - alas the diameter is not 3".
Once my 335 is done I will definetly post up some pics for you guys to see. Maybe we should actually organise a meet up as the BMW club does not have enough meets if you ask me.
You will not go wrong with the 335 coupe. It is a MACHINE!