i want some upgrades

i have my ram you can see what it is by description i want some engine upgrades and interior. engine wise i have a cai tb spacer and super chips programer what else can i do on about a 500 budget and keep my 10mpgs lol also interior has the following a 8 inch sub under the back seat camo seat covers front and rear custom rebel flag headliner and a skull 4x4 shift knob what else can i do besides go ghetto on it i really dont want a bunch of lights and crap or speakers its a dd and kinda a show truck