New lancer owner, need advice

Hello all,
I recently bought lancer 2002 LS.
I need some advice on upgrading my lancer without sacrificing the fuel efficiency or if you can improve the fuel efficiency that would be even better.
Right now what i'm thinking of installing is new spark plugs(i'm sure the previous owner never changed the spark plugs), and air filter.
Please give me any advice regarding the spark plugs and air filter (what model, manufacturer, cost, etc).

If you have any info regarding improfing the fuel efficiency, that will help me a lot (I drove 60miles/day to work :( )
Thanks

for spark plugs you should probably get some bosch platinum's. they are good reliable plugs, and instead of a new filter you should just get a new in take. If you do get a new intake try to find something from aem. i'm not sure on the price in your area but i've usually seen them for about $150