As can be seen from the photo, the trumpets on this airbox are larger in cross-section, and they thus have a greater taper angle as they converge towards the throttles. It is stated that the trumpets are also longer than those of the "small-trumpet" airbox (approximately 18 cm vs. 15 cm according to e30shop ). The cost is also higher at roughly $1250 (plus $300 if you want the installation kit).

It appears that this airbox is patterned after a "newer" Motorsport airbox than what was used to create the small trumpet box. Possibly this larger one is from the 1990 time frame. This would tend to bear out as the S14 engine made a steady progression through the factory Touring Car program towards larger displacement and bigger intake and exhaust tracts (to handle the larger airflow demands).

Note, however, that the German tuning community describes this airbox as boosting low end torque, as well as requiring a longer duration camshaft (which implies peak torque at higher rpm). One does not generally think of large cross-sectional intake pathways as contributing to low end torque production, since the large area leads to low flow velocity at lower rpm. But perhaps the taper of the trumpets, or simply the increase in plenum volume has an affect. And remember that the definition of "low-end" is relative. If your torque peak occurs at, say 6500 rpm, due to aggressive camshafts, then 5000 rpm might be considered low-end.

Also note that longer intake runners (trumpets) do tend to lower the rpm at which the airbox contributes most to torque, and the trumpets (runners) are quoted as being 2-3 cm longer on this large airbox when compared to the small trumpet airbox. Be conscious that this would probably push the airbox very close to the driver's side strut tower. It is already quite close on the small trumpet airbox. It is difficult to really pinpoint the difference in trumpet length from the photo comparison.