It's not unusual to feel the fans on through the steering wheel, I do, but just sound like a normal fan, as loud/vibraty as yours sound could be bearings on way out, or a internal magnet detached itself and rubbing.
Th heat soak bit is a very overdone bit of nonsense imo, it matters not what material the rad is so long as it can sense water temp, the msd "uprated" read BOG std fan switch from another car has a different hysteresis ie the span from on to off is less, which was the main problem to start with.
If you still have the oe intercooler and air deflector plate this will ensure your fans takes a long time to cool down as the heat can't rise as it would naturally.
tabetha