Ohhh Charlie, where did you hear such crap from? Airbag compliant bullbars have been on the market as long as ARS fitted vehicles have. Also when you submit your application for a vehicle modification (ie body lift) items such as interference with airbags and the like is taken into consideration.
CHISEL - There might be a lot of 4wds running around with 'mildy illegal' tyres, but I bet I have access to more ticketbooks than 4wd's!! Nah seriously, tyres which fall outside the modification limits do render the vehicle as 'non compliant' with the TORUMS. As viewed by the insurance company, a 'non compliant' vehicle should not be on the road, therefore should not have been involved in the traffic accident, therefore should not be in a position to make a claim, therefore said insurance company should not pay out the claim..... Get my drift.... I have seen it happen!
Another scenario which might cause trouble could be when I was living in another State and also in a different profession. I was running 33 Mud Terrains under my Pajero. Looked great, chics dug it, but I couldnt turn left real well!!