to get the most from your stage one map, you could get a full cat back exhaust system, larger downpipe/sports cat, good panel filter or CAI, Forge 007p, Forge TIP.
These arent just for stage 2s, they can be used on stage ones to get the best from the MAP. All r-techs mapped are custom setup to each car, so the more supporting mods the better figures you should get from a healthy engine.