1998 2.5 dse....

Hi landy lovers....been underneath messing around and noticed that (I think) that there is a acoustic plate?? missing from the bottom of the gear box.. now mine is a manual box and i always thought that its a bit noisy on the road.. a bit 'transmisiony' .. if you know what i mean.. if i find a bottom plate would it be worth buying it.. or not to bother.. will it make a differance?? as always your comments would be very much appreciated... by the by any one got one for sale?? thanks guys(and gals)....