I would recommend exhaust like CMI or Lightning or Stainless Marine. And maybe send the ECM out to AZ Speed and Marine for some upgrade.
Exhaust will run $1500-1800 bucks and ecm reprogram about $275. I do have a set of CMI exhaust with only 2 races on them that I took off because I went with Tubular Headers. I will let them go for $900 They are Aluminum with stainless risers in excellent condition