Cluth upgrade for 2l tdi a4 170 mapped 220bhp

I have a Audi A4 2007 B7 170. I have had the car mapped to 220 increasing it by 50 Bhp but time has now come where im due a cluth and fly wheel but want a upgrade. Does anybody have any recommendations on what i should get? Been told dark side developments are good? Plus i got a consistent dpf problem flashes up with the glow plug light with the dpf light and sometimes the engine management light the car goes in limp mode here and there then goes back to normal but throws out black smoke which is a bit odd. Been told i need a new turbo which i doubt. Any help and advice will be very much appreciated. Thank you