There's a choice of three engines in the Genesis, as opposed to the V-6 and V-8 originally offered. Upgraded for 2012, the 3.8-liter base V-6 now makes 333 horsepower, up from 290 hp, while the 4.6-liter V-8 — like all three engines — teams with a new eight-speed automatic transmission for slightly better fuel economy.

The two versions, designated 3.8 and 4.6 after their engines, start at $34,200 and $44,500, respectively.

But the engine getting everyone's attention is the all-new 5.0-liter V-8 with 429 hp and 376 pounds-feet of torque. It's a monster and still returns 16/25 mpg city/highway. Called the Genesis R-Spec, this top trim level is priced at $46,500 fully loaded.

Typically when an automaker goes through the trouble of coming up with a performance name like "R-Spec," the car itself is aggressively tuned, the ride quality suffers, and comfort is sacrificed for pure performance. One look at the 19-inch wheels wrapped in run-flat tires, and I thought I was in for a rough ride.

The second I turned out of the parking lot, the Genesis felt … sedate, like I was riding in a posh luxury car such as a Lexus LS 460 or even a Mercedes S-Class. Indeed, the R-Spec is much more of a grand tourer than a sports sedan.

The power comes on in a silky-smooth delivery, no doubt enhanced by the new eight-speed automatic transmission. There is no severe revving to launch you from the line. That smoothness matched to the eerie Lexus-quiet cabin and pillowy ride makes the R-Spec deceiving. It doesn't seem like you've gotten to 60 mph in just over 5 seconds, but you're there faster than you thought, and by your second thought, you're at 80 mph.

If I had to travel hundreds of miles in a straight line, the R-Spec would be a great choice. Even on twisty roads through the Nevada desert, the R-Spec handled well with lots of grip, but it was a bit hard to judge your speed going into corners, which made some sweeps a bit wider than I wanted.

Then I stepped into the Genesis 3.8. Aside from the wheels, the cars look nearly identical inside and out, but there is a world of difference from the driver's seat.

The difference in power isn't the most significant drop in driving pleasure. Whereas the R-Spec was deathly silent, the V-6's smaller wheels and tires led to much more noise and vibration. If I had taken the V-6 out first, it probably wouldn't have distracted me much, but the difference was stark.

The suspension was also less tuned in. Over road undulations, the 3.8 had a floatier ride.

Traveling at 70 mph and higher on the highway was still a pleasant affair. Unless you crave power, the V-6 has enough — more than most cars in this segment, in fact.

But my co-pilot and I both preferred the R-Spec. To the tune of an additional $12,300? I'm not so sure.

The carryover 4.6-liter V-8 wasn't available to test. It is the same engine that won over our staff for its refinement, much like the 5.0 won me over in the 2012. It still gets 385 hp on premium gas and 378 hp on regular, but the new eight-speed bumps mileage up 1 mpg on the highway to 17/26 mpg.

Mileage for the 3.8 is 19/29 mpg, and the 5.0 R-Spec gets an impressive 16/25 mpg despite busting the 400-hp mark.