Used airbag setup, Newbie so need input on these parts please!

[DENALI]

Looking to bag my 54 with a mustang II front and possibly a TCI 4 link or possibly a no limit trailing arm setup. Anyhow a local guy to me wrecked his car that had this setup installed on it. Its had about a year of use but I don't know anything about these parts as to what they are etc. He doesn't seem to be much help either, just a kid who said he paid $2700 for all of it when they put it in the car (96 buick). I don't know if the airbags themselves would work for me but what about the rest of it? Is it decent quality stuff? He is asking $700 for everything. I don't want to spend a whole lot of money so every little bit I can save helps. Please give me some input on this stuff THanks