For The 3.1 I would get the following. Iridium Plugs (you will never have to change again), Delco wires, Fuel filter (may be a pita depending on rust), Air filter (performance drop in if wanted).
Do a seafoam intake cleaning, clean the Maf and throttle body, run a can of seafoam in a half tank of fuel before changing the fuel filter. The following is from rockauto.com look for a coupon code online for 5% off. they are always available.

AUTOLITE XP606 {#XP606DP2} Iridium (Rebate/Promotion Available!) Info
.060 Gap; OE Style
$4.03
Wires......
ACDELCO 9726UU {#88862391} Professional Info



$24.79
Fuel Filter.......
ACDELCO GF578F {#88915468} Professional|Durapack Info



$8.39