The best performance parts are from Australia since they mainly had slant six's and commonly race them. Indeed, they have a special six we never had, I think they call the "Hemi 6". A company in the U.S. imports tuner parts, called "Aussie Parts" or such. Search for the "Hurricane" intake here. Runs ~$500, but would win gasps at car shows, if that is one of your goals.
Your car would be great for an "Al Bundy" sleeper look. Open the hood and see what the shoe salesman stuffed in there.