a FFB wheel can correctly only oscillate on it's column axis - round and round as it were. The vibrations from your engine won't be in the plane (at least, if they are they are massively negligable compared to the vibration in the X,Y,Z planes, which a FFB wheel cannot transmit).
I could say that my exhaust rattles a bit in real life, so can I have that rattle in my steering please - both are silly, because both have nothing to do with steering axis.
And besides, I can't feel the engine vibration through my steering wheel unless I REALLY think about it. It's so small that a FFB couldn't vibrate such tiny amounts.