I did the elbow mod and this:
View attachment 29081
I haven't a clue if there are any more horses in there, but it sure sounds good at 3/4+ throttle and I get better initial response from a stop.
Except for a supercharger, I chalk up all the intake and exhaust stuff on 3rd gens to personalization of our rigs. They mostly result in small gains, but are definitely worth the hobby of it all.