Simply put the 3.8 litre is one of the best motors made. My '95 Regal GS has 37,500 miles on it and it runs like a dream, I have never had a problem with it.
My 1995 buick has 215,000 miles on it. It has the 3.8 engine. I drive mostly highway, change the oil every 4500 miles. Only uses 1/2 qt. oil between oil chages. No major problems. Replaced alternator, battery, water pump, intake manifold, tie rods. Never left me stranded.
I own a similar Regal that has about 375,000 miles on it yet it runs as if it was brand new. It has the 3.1 engine, and it has never been worked on, besides at about 300,000 miles I put on new valve cover gaskets (took 1 evening to replace). The car began losing its clearcoat and I eventually got the car repainted about 4 months ago. The car was practically rust free before I got it painted. The underside is still virtually rust free probably due to the fact that I clean it and spray oil on it about 2 or 3 times a year. I always change my oil between 3 to 4 thousand miles, and I use Valvoline or Castrol 5W-30. I plan on keeping this car forever. I truly believe that this is one of the best cars out there.
We have a 1995 3.8 engine Buick Regal, it has around 90,000 on it. We had to replace the alternator just after the warranty ran out.
It has since day one started as quickly as a car can, and still does, that's 14 years of starting. It does have a real slow oil leak, not sure where it is coming from, maybe the oil pan, but that's just a guess.
All in all it has been a excellent car and it belong to my wife.
I bought a 2006 Buick Lucerne, and that is the first year they came out, so far it's been perfect, never had to take in in for nothing, I hope I didn't just jinx myself. It did come with 48 months or 50,k warranty, whichever comes first.
Nice car, but not that much power, but it gets good gas mileage.