If you want NEW front air springs/shocks, you have to buy from the dealer.
www.fordpartsnetwork.com is a great source.
if you want remanufactured air springs/shocks,
www.americanairsuspension.com
the remans will be of the "gen 1" variety(steel stock, new rubber bladders)
the new units will be of the "gen 2" variety(plastic stock/new rubber bladders)
Strutmaster's "remanned" units come with ARNOTT rubber(stamped right on the side of the air bladder)
The choice is yours. Most go remanned to save cost. However, keep in mind, if the car is dropping now, you have had a small leak for quite some time. therefore, your compressor has already been working "overtime". The longer you wait, the more expensive it could get.
I have experience in both strutmaster's products, American Air Suspension's products, as well as many coil conversions.
I'd have to really lean heavily towards Eddie at american Air...he's always been MORE than good to me, and all who I have referred to him.
Good luck in your decision.