It runs fine, just not to its full potential. I am storing it for a time to bank some $$ and then get to work nursing it back to a healthy state. Then I will look at some basic performance mods.

Also check for leaks from the plastic coolant elbows that are near the water pump. They are also a known problem area.

If they are bad, replace them with the metal units.

Also look for signs the Lower intake manifold gasket has ever been replaced. They are the other major problem area that can dump coolant straight in to your oil if you are not careful.

Yep 1st thing I checked were the elbows. They're fine. They're plastic so I'm assuming they're OE and haven't been replaced. Regardless, they definitely will be getting replaced with metal ones. Cheap, easy fix for the potential headaches it solves. I've heard mechanics refer to this as "bullet-proofing".

I currently have a 1999 Regal GSE that is bone-stock. I'm considering installing a slightly smaller pulley on the supercharger but have heard that can potentially cause piston chipping and also transmission problems. I'm not interested in making a "racer" I just want to give the car a little extra oomph when I want it. I'm also interested in any advice/recommendations for additional bolt-on or tuning mods for the car. Thanks in advance.

Same one we've been discussing or a different one?

I this is the same 200,000-mile car, I'd make sure the SC is in good condition and has fresh oil before handing it extra work.

. . . probably from excessive detonation from the increased cylinder pressures. Your stock SC pulley should be 3.8" . Every 0.1 you go down is worth around 3-5HP depending on your altitude and ambient temperature. Go in small increments. Go below 3.6" and you have to start worrying about issues more than otherwise with no other compensating modifications. Lower altitude and hotter ambient air equals more worry.

If this is a 200,000-mile transaxle I'd have some concerns unless I knew it led an easy life for 199,000 miles. One thing you can do that is almost never an issue is add a transmission cooler. Even if you don't do anything else to the car. The transaxle will thank you for it.

Based on this and the possibility that it has 200,000 miles on it I'd say go conservative. Especially if it is your daily driver and/or only car.

The sky'* the limit with this platform. I've read about folks changing to a 180-degree thermostat, cooler plugs (so they can boost harder), undersize pulleys, bigger injectors, cold-air induction, PCM tunes, exhaust systems, etc. My take is start with things that make the car'* life easier then work your way to where you want to be. For example: in general a freer-flowing exhaust system would make life easier on the engine to push exhaust out, and at the same time get you a little more power. That said, on this platform the exhaust system really isn't getting in your way until you add 50HP+ so I wouldn't start there. Maybe reduce your SC pulley by 0.1" and go from there. This would be your most bang for buck and is a fairly safe change.