Cadillac STS

Cadillac STS: Which Version Should You Buy?

The Cadillac STS in this catalogue is a Sedan offered from May 2005 through May 2011. The choice is between the original 1 generation, with five versions, and its restyling, with seven versions. Every listed STS uses Gasoline, an Automatic gearbox and either RWD or AWD.

The Cadillac STS in this catalogue is a Sedan offered from May 2005 through May 2011. The choice is between the original 1 generation, with five versions, and its restyling, with seven versions. Every listed STS uses Gasoline, an Automatic gearbox and either RWD or AWD. The central buying decision is whether to prioritize the 3.6 AT’s lower kerb weight, the naturally aspirated 4.6 AT’s balance of performance and output, the 4.4 AT’s maximum power, or the added traction of AWD.

Cadillac STS generations: original or restyling?

The original 1 generation ran from May 2005 to August 2007 as a Sedan with five versions. Its range included 3.6 AT models producing 255 hp, 4.6 AT models producing 325 hp, and a 4.4 AT producing 476 hp. The 3.6 AT and regular 4.6 AT used a 5-speed Automatic gearbox, except for the 476 hp 4.4 AT, which used a 6-speed Automatic. Buyers could choose RWD or AWD, although the 4.4 AT was listed only with RWD.

The restyled 1 generation ran from September 2007 to May 2011 as a Sedan with seven versions. Its 3.6 AT output rose from 255 hp to 306 hp, a gain of 51 hp, while displacement remained 3564 cc. Restyled 4.6 AT versions produced either 320 hp or 325 hp. Most used a 6-speed Automatic, although both 306 hp 3.6 AT versions retained a 5-speed Automatic. The 476 hp 4.4 AT continued with a 6-speed Automatic and RWD.

For a buyer comparing the generations, the clearest numerical change is in the 3.6 AT: output increased by 20%, from 255 hp to 306 hp. The naturally aspirated 4.6 AT did not receive a comparable power increase; depending on the listed specification, the restyled versions have 320 hp or 325 hp.

Cadillac STS engine options and specs

Because several entries share the same version name, power, drive and production period are shown together to distinguish them.

Power per litre clarifies what each engine offers. The 255 hp 3.6 AT develops about 71.5 hp per litre, while the restyled 306 hp 3.6 AT reaches about 85.9 hp per litre. The 325 hp 4.6 AT delivers about 71.2 hp per litre, and the 320 hp 4.6 AT delivers about 70.1 hp per litre. The Turbo 4.4 AT leads decisively at about 108.9 hp per litre.

The 4.4 AT also provides the greatest torque at 595 Nm. That is 168 Nm more than the original 325 hp 4.6 AT and 249 Nm more than the restyled 306 hp 3.6 AT.

Cadillac STS performance and fuel economy

For maximum performance, the 476 hp 4.4 AT is the clear choice: it reaches 100 km/h in 5 seconds and has a 265 km/h top speed. Compared with the restyled 306 hp 3.6 AT RWD, it is 1.2 seconds quicker to 100 km/h and 8 km/h faster at the top end.

Among versions with complete fuel-consumption figures, the restyled 320 hp 4.6 AT RWD records the lowest figures: 13.9 L/100 km in the city, 9.1 L/100 km on the highway and 11.5 L/100 km combined. Its combined figure is 0.9 L/100 km below the 12.4 L/100 km recorded by the 255 hp and 306 hp 3.6 AT RWD versions. Fuel consumption for the remaining versions was not measured.

Cadillac STS weight, ground clearance and wheel specs

Every listed Cadillac STS has 159 mm of ground clearance and a 66 L tank, so neither measurement separates the versions. Kerb weight does: original RWD versions are 105 kg lighter than their corresponding AWD versions for both the 255 hp 3.6 AT and the 325 hp 4.6 AT.

Weight per horsepower favors the 4.4 AT at about 4.1 kg/hp. The original 325 hp 4.6 AT RWD follows at about 5.5 kg/hp, while the restyled 306 hp 3.6 AT RWD records about 5.8 kg/hp. The least favorable listed ratio belongs to the original 255 hp 3.6 AT AWD at about 7.4 kg/hp.

No exterior dimensions or wheelbase measurements are supplied in the data, so Cadillac STS dimensions and wheelbase are not measured here.

Which Cadillac STS version should you buy?

For the strongest all-round numerical case, choose the restyled 3.6 AT RWD with 306 hp. It weighs 1782 kg, reaches 100 km/h in 6.2 seconds and has a 257 km/h top speed. Compared with the original 255 hp 3.6 AT RWD, it adds 51 hp, cuts the acceleration time by 1.2 seconds and raises top speed by 28 km/h, while weighing 3 kg less. Its measured consumption remains 17.7 L/100 km city, 9.4 L/100 km highway and 12.4 L/100 km combined.

Choose the restyled 320 hp 4.6 AT RWD if measured fuel economy and the 6-speed Automatic matter most. It has the lowest supplied consumption figures, reaches 100 km/h in 6.2 seconds and weighs 1835 kg. Against the restyled 306 hp 3.6 AT RWD, it adds 14 hp and 79 Nm but is 53 kg heavier; the 3.6 AT also has a 7 km/h higher top speed.

Choose the 476 hp 4.4 AT RWD when performance takes priority. Its 5-second acceleration, 265 km/h top speed, 595 Nm and approximately 4.1 kg/hp are the strongest figures in the range. Fuel consumption and gross weight were not measured, however, so the supplied data cannot support a complete running-cost comparison.

Choose AWD when traction layout is the deciding requirement, while accepting the weight difference shown by comparable versions. In the original range, the 325 hp 4.6 AT AWD is 140 kg heavier and 1 second slower to 100 km/h than the 325 hp 4.6 AT RWD. In the restyled range, the 325 hp 4.6 AT AWD is also 140 kg heavier and 0.8 seconds slower than the corresponding RWD version.

Overall, the restyled 306 hp 3.6 AT RWD offers the clearest improvement over its earlier equivalent, the restyled 320 hp 4.6 AT RWD supplies the best measured economy, and the 476 hp 4.4 AT RWD is the unambiguous performance choice.