At about 25,000 miles I began to detect increasing road noise inside this car. The local Pontiac dealer diagnosed it as front wheel hub bearing noise and replaced both front hubs (more than $1000). Unfortunately this was not the root cause of the problem. When replacing the hubs didn't solve the problem I replaced all four of the original tires ( even though they had lots of tread left on them) and the noise immediately disappeared.
The tires that were originally installed on this car by Pontiac were Goodyear Eagle LS P225/60R16. I replaced them with Michelin X-Radial DT's of the same size.
So, if you are experiencing increasing road noise in your car and it has Goodyear Eagle LS tires installed, this may be the culprit.