I've maintained and ground run a number of P2006Ts for 7 years or so.
On cold damp mornings in particular, the engines do ice up but clear quickly with the use of carb heat (even with a cold engine). Once the engines are warmed up to operating temp (oil temp 50°C) then they're fine and don't tend to ice up. I've never heard anyone reporting issues in flight be it during training, cruise, IMC or whatever.
I always taxy them with carb heat on 'hot' on cold, damp mornings.
Carb heat is provided from hot air ducted from a shroud over the muffler (like Lycomings) feeding the single air box that is normally used on the certified 912S.