First off, PS and AC are for the weak. :D
Second-If you plan on running air tools of any kind, a tank is a must even for a 10cfm york. If all you are doing is airing up then its not necessary by any means.
Researched it extensively for my 40, and as soon as oil pressure and brakes are resolved it's next. The hardest part is getting one mounted. After that its all cake. The best Yorks to use come out of 80-83 volvo station wagons and sedans, 10cfm, upwards of 300 psi (comparable to most portable...