I'm not sure about the specific part no's but I have bought NGK's(wires/plugs) thru http://www.speedycarparts.com/ . The site has a way of selecting the parts based on your selection of vehicle make, model etc.. pretty easy. There are of course other sites and some may be better but this is just one I have used and like due to their prices, ease of use and selection. As for the gap check your users manual it should be stated there.
I replace my plugs once a year and wires every two years. Oh yea and don't forget to put anti seize compound on the spark plug threads.
91 Legacy LS 2.2
Good luck
Sam