Stupid Question but im gonna ask anyway

[STSJohn]

i have 2 STS's one is a 2000 and the other is a 98, the 1998 has the Z package (Found that out a couple minutes ago on the onramp of I-4). The 1998 Feels Faster then my 2000 Not talking about top speed but 0-60/0-100. is it possible that the 98-99 model is faster then 2000-2004 Models?

another question whats the top speed on the Z-package? i was up to 138 before i ran out of pavement

[67coupedeville]

The Z package should take you right up to around the 150 MPH mark. I am unsure about the 0-60 times though .

Spence

[JasonA]

i have 2 STS's one is a 2000 and the other is a 98, the 1998 has the Z package (Found that out a couple minutes ago on the onramp of I-4). The 1998 Feels Faster then my 2000 Not talking about top speed but 0-60/0-100. is it possible that the 98-99 model is faster then 2000-2004 Models?

another question whats the top speed on the Z-package? i was up to 138 before i ran out of pavement

There are variations in all of the cars, so there will be SLIGHT differences in general. But the powertrains are RATED the same between 1998 and 2000. The 2000 engine is actually more advanced, and optimized to run regular fuel (whereas your '98 is optimized for premium). The "Z package" merely consisted of Z-rated tires and a higher speed limiter (indicated above). A standard STS was shod with H-rated tires, and is good to 130 mph. All of the cars are physically capable of 140-150 mph, but the speed limiter was installed according to the tires equipped at the factory.

Here's a chart I compiled of all available reliable data I found (like instrumented test from magazines, etc). The 2001 STS (identical to your 2000) actually outran all of the '98 cars. Your 2000 could be slightly slower and your '98 could be slightly faster, but "seat of the pants" feel is always hard to verify. You should put both of your cars on a chassis dyno and see what they get.