It would help if you told us what kind of ranger you have, engine size trans type 4x2 or 4x4. Also there really isn't much it's a ranger so it doesn't really get very loud. You could cut off the muffler and cats however the act of removing the cats is against the law. Could try changing mufflers, really the best way altho not the cheapest, a 5.0L swap.

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91 Ranger 4.0L
5spd
ext cab
4x4
sylvania ultras