RE: Speed Limiter
I am in Canada and my 98 GM Canada manual spells out the speed limiter as follows:
Deville & D'elegance top speed 180 kph ( that would be about 115 mph)
Concours top speed 210 kph (that would be about 130 mph)
It also shows the following:
Deville & D'elegance 0 - 60, 7.8 seconds with 3.11 axle ratio & 275 HP / 300 lb-ft
Concours 0 - 60, 7.5 second with 3.71 axle ratio & 300 HP / 295 lb-ft
To remove the limiter do as others have indicated. I would caution you to make sure you have properly speed rated tires if you do so. Nothing worse than throwing a belt at 125 mph! It tends to raise one's heart beat a tad. I know, I did it in my 35 year old muscle car on BFG's that were S rated. First the right rear and a split second later the left. Hang on!