ZZP has always done right by me. No complaints here. As stated before they have all kinds of useful parts for your GP. But as others have stated, it is best to work on your exhaust, aka U Bend Delete, a bigger down pipe, ie 2.5 to 3" would be best, a cold air induction (CAI) to allow more air into the engine, maybe colder spark plugs (Autolite 104s perhaps) and getting a colder TState (180), get those things done first and then worry about dropping a pulley size.
With those simple mods I mentioned you should be able to safely drop to a 3.5 or 3.4 pulley. Also it would be GREATLY suggested that you get a quality tune slapped on your car before dropping the pulley to avoid any potential bad outcomes.
Just my 2 cents on the topic.
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