i dont know about the costs, i imagine the LCD is less expensive being as how your only buying the screen instead of the whole HU w/ the LCD. but installation (unless you do it yourself somehow) might get costly, and i have no idea how to wire it all up and how much that would cost. i bet it could be less. and i dunno what you could do wiht the OBD. maybe put it in the glove box?
<img src='http://img268.echo.cx/img268/1430/zkwsig23iq.jpg' border='0' alt='user posted image' />
1996 328is Black
Suspension: MB Motoring 18x8, Kuhmo Supra 225/35/18ZR
Audio:Eclipse CD3414 HU
Lighting: ZKW W/ DDE PLUS