This morning on MSN / MotorTrend they had the story "15 optional enginese worth buying"!

 

http://editorial.autos.msn.com/15-optional-engines-worth-buying?icid=autos_5982

 

The end result was the following list:

 

Audi A6 - Upgrade to the TDI V6

Buick Regal - Upgrade to the Turbo I4 {they state this is German Entry Lux alternative worth the money}

Ford Fiesta - Upgrade to Ecoboost Turbo I3

Jaguar F-Type - Upgrade to Supercharged V8 from Supercharged V6

Kia Optima - Upgrade to Turbo I4

Subaru Impreza - Upgrade to WRX

VW Golf - Upgrade to the GTI

Jeep Grand Cherokee - Upgrade to 3L EcoDiesel V6 over regular V6

Mazda CX-5 - Upgrade to Skyactiv 2.5L I4

Lexus IS 250 - Upgrade to 350

Ford F-150 - Upgrade base to 2.7L EcoBoost V6 option

Ram 1500 - Upgrade base engine to 3L EcoDiesel V6

Dodge Challenger SRT - Upgrade to Hellcat as cost is only $63 per pony. Cheap

MB SL63 AMG - Upgrade to SL65

Chevy Camero SS - Upgrade to Z28 or LT1

 

So with this list of optional engine upgrades that they feel you should do, I felt it was a great conversation to have here as there are plenty of other auto's not mentioned here that have optional engines that should be done also.

 

Sound off on what auto's you feel should be had with the optional engines!

 

Any VW product with the diesel.

Any full size pick up with the diesel.

Not a fan of the turbo 4 in a mainstream sedan, any available v6 upgrade. Other than the Mustang, where for some real as on I would like the ecoboost.

Any Cruze or Sonic with the 1.4T instead of the 1.8.

The Regal is 2.0T base now, so the only upgrade is a GS version and is only needed if you are a performance junky.

If you're already buying a fairly loaded Verano, the 2.0T makes for a sensible upgrade, but you can only get it if you are already well into the option packages already.

The Optima with the 2.0T is fast, but is a NHV nightmare... the car itself is fine, but Kia needs to work on refinement of all of its engines.

The Fiesta I3 Ecoboost is a fantastic engine... better than the base-4 in NHV, drivability, and MPG. You'd never know there wasn't a big-4 under the hood... I have a review coming on this one.  

The IS250 engine is pathetic... 204hp at 6400rpm and 184 lb-ft at 4,800rpm from a 2.5 liter V6? For comparison, the Cadillac ATS 2.5L is equipped with a 2.5-liter 4-cylinder engine good for 202 horsepower at 6,300 rpm and 190 lb.-ft. of torque at 4,400 rpm. The IS only manages 30mpg on the highway while the ATS gets 33mpg.

The Jeep Ecodiesel is a nice option, but due to its pairing with other packages, it becomes a $7500 upgrade

The Z/28 isn't an engine option... it's an entire car package... and one that is $70k... what a useless suggestion. The SS Camaro is sufficient enough of an upgrade for 99.99999% of people.

On the mainstream cars I think the engine upgrade is always worth it. Who wants the weak base engine? The only time it is not worth the upgrade are cars like the Z28 as Drew said and M and AMG models would fall into that class. If you aren't doing track days you don't need it. But to use the Camaro as an example you would still upgrade to the SS, just maybe not all the way.

On something like a Bentley where the base engine is already 550-600 HP, there is no reason to upgrade there. But the only sub $75000 car I think the base engine may be better than the upgrade is the E250 bluetec because it gets 42 mpg and the V6 is old news in that car.