You could always try making the headlights tall or long I dunno if it would look better. Otherwise it is as big as it can be. You'd have to edit the .dff file and you'd need a program that can edit that kind of file. Gmax does it if you have the right scripts Kam's scripts or something like that. I changed the delorean to have all 4 headlights light up instead of 2.
;(ah) front lights (0 = long, 1 = small, 2 = big, 3 = tall)
;(ai) rear lights (0 = long, 1 = small, 2 = big, 3 = tall)
;(aj) vehicle anim group