they use the same pumps, they get them from the same company.
the FASS was never tested to take the air out of the fuel. it was also never tested to improve the fuel spray. all the pics that FASS had was from the fuel preporator. which was desinged by charlie the father.
i have pages of court transcripts that show that and more.
the AD is hands down quieter than the FASS.
i'll post some comparison pics too
http://www.cumminsforum.com/forum/xtreme-diesel-performance/56082-airdog-fass-comparison-pics.html