I have owned this car for about 6 years. It had 47k mile when I bought it. I drive this car very hard and I have 164k mile on it. I know this is crazy but I have never replaced the timing belt (not recommended). I have had to replace the O2 sensors but that is about it for repairs. It has a good ride, smooth transmission, and good pick up (especially in PWR mode). This is the best car I have owned.
PWR Mode - Smooth Transmission - Reliability
All four O2 sensors went bad in the same year but this does not cause the car to stop running. More horse power in the GS 300.
Bought it new and have had a love hate relationship since. Overall quality is very good, but performance stinks. Sporadic shifting pattern, especially after slowing and making 90 degree turn, then accelerating again will drive you nuts. Also, shifting pattern in stop and go urban traffic will drive you even nuttier. computer and ESC don't have a clue how to respond. Recall/upgrade of ESC was done in 1999, but really didn't fix the problem. Dealer acknowledges this as an engineering problem typical to the car - big, unforgivable mistake for a car in this price range
Overall quality of fit and finish
Make it responsive to the driver's needs, make it handle like a sports sedan should handle, and generally make it fun to drive.
My Lexus GS 300 is by far the must durable automobile I have ever owned. While this has come to be expected from Lexus, I am still impressed with its reliability. However, the rest of the car is not perfect, as acceleration is just as mediocre as when I bought it in 99, and the interior is not particularly roomy. The car does handle decently well, however, but don't expect a canyon-carver, like a 5-series.
Bad news for anyone looking to buy a 1999 GS 300, you can NOT have mine! I have spent over two years looking at possible replacements but know I won't be happy with anything else. Also, once you have been to a Lexus dealer for service, all of the others are second class. We bought the car pre-owned, commuted in it 60 miles/day (Washington DC) for 4 years and at 115K miles it still seems new inside and out. Interior materials are first rate especially the wood.
The Lexus ownership experience is great. 10-way power driver and passenger seats. Power tilt/telescope steering wheel. The paint. The wood.
Since it's too late to expect improvements in a 9 year old car I'll just alert you to two performance issues. The car lurches when you first press on the gas. It is hard to start off smoothly. And on the flip side, the brakes are late to grab, annoying in stop-and-go traffic.