Apologies in advance for the crappy Iphone pictures.
Here you can see the intercooler and the stock bumper cross member.
This is the Tuff mounts and crossmember, ready for bull-bar fitting. Note the unimpeded air exposure to the intercooler and protection from underneath.
I understand what Northside is saying in regard to single large vent openings against many small ones.
This has to work better though. Total opening area of 0.264 sq metres on the bar, compared to 0.072 sq metres on the stock bumper. The extruded alloy mesh on the bar will impede air flow to some degree though...but also lessens the possibility of intercooler stone damage.
To test the theory in a very un-scientific manner, I mounted a wireless household wind anemometer in the front centre of the intercooler. I drove along at 70km/h and noted a wind reading of 42km/h. I then mounted the anemometer in the same spot on my old series 1 STX with the stock bumper and did the same drive...and got a reading of 36 km/h for the same conditions.
So I am pretty confident that no ill-effects will present.
Beer time at the end of a long day. Everything swapped over from old to new!
Anyone interested in a 2006 Navara 2.5 manual with 90K km in real good nick?