Power versus MPG

In selecting my next Cadillac, I am drawn the to highest performance models available within my budget.  More is always better right?

My model for the ‘right’ 0-60 time for a sport sedan is 5.5 to 6  seconds this year.   Performance of cars as a whole changes over time, as automobile performance improves.

The current CTS DI 3.6L will do 0-60 mph in 6.3-6.5 sec.  The CTS should be below 6 seconds with 304 hp, but it also gained a bit of weight with added features, and has fuel economy minded gearing.  Yes I recognize that is kind of in the same range, but let’s assume for this discussion that quicker is important.  So the CTS 3.6L is just on the upper edge of my desired performance envelope, and is right in the right zone for MPG.

Now, the 2006-2009 STS-V with 469 hp will go 0-60 in around 5 sec, or as Cadillac measured in under 5 seconds.  However, this model gets 19 mpg highway compared to the CTS DI 3.6L V6 MPG of 28 MPG highway.

One compromise candidate is the 2005-2009 STS 4.6L V8, with the 320 hp VVT Northstar.  This sedan gets very close to 0-60 mph in 6 sec in most tests, and has fair fuel economy at 24 mpg highway.

The new Gen2 CTS-V with 556 hp supercharged 6.2L V8 will do 0-60 mph in under 4 seconds with a Cadillac test driver, or just over 4 seconds with a magazine writer driving.  The new CTS-V is still outside of my budget however, and also gets 19 mpg highway.

The 2006-2007 Cadillac CTS-V with 6L LS2 V8 engines would do 0-60 in under 5 seconds, and are rated at 24 mpg highway.  So these are interesting, but they will soon be out of warranty.  I like to keep my daily driver under warranty, so if there is an issue I can simply drop it off for service, pick up a loaner car, and be on my way.  These are also only available in manual transmissions.  A manual is okay for me, but is challenging for other members of my household.

So this thought process leaves me wondering if I should change my target from “as quick as possible” to “as quick as possible and still get more than 24 mpg highway”, or similar.

In this range that 5 mpg costs around $1000 per year given my mileage per year and average gas prices.  So would you pay $1000 per year for another 150 hp, or 47% more power?  I suppose over the 5 years I plan to drive the car that is less than the cost of a Supercharger or similar power adder.

How many MPG is more power worth to you?