I have a single compressor ARB in my landcruiser and a Viair 400 with a 5 gallon tank in my Transit. They both seem to fill tires at about the same rate...Viair might be slightly faster, but the ARB is really loud. ARB is mounted under the hood. Viair outside under the passenger seat. How often will you really use them? They are nice to have, but... I travel a lot, much of that off road and use the one in my transit mostly for filling bike tires. EDIT...oops, I forgot you said you had airbags.