Many people commenting here... and many missing the point.
The problem is not in the helicopter but in the pilot.
I don't know if the R44 is legaly certified for IFR, but anyway an IFR RATED pilot can fly safely (legally or not) any helicopter in foggy weather if it is equipped with attitude indicator, altimeter, variometer, anemometer and compass. Theoretically you should automatically change to IFR rules but even if you still consider yourself in VFR (which is cuestionable, because you are not relying on your eyes to guide the flight) you need the help of the "five basics". If you have not experience with instrumental flight and you get caught in an IMC situation and you fail in an inmediate return to VMC, you are almost done, no matter how "stable" your helicopter is.