Performance Commuter Sedan

Based on my experience and the criteria you mention, you will find the Hundai Genesis meets your requirements in terms of engine performance, reliability, and comfort.

Acceleration is very good with the V-6, even better with the V-8, and highway gas mileage is pretty good for such a large car (I consistantly get better that the EPA rating on long trips). I own a V-8, and the easy access to power at any point on the rev range for merging and passing makes the car fun to drive.

Reliability is good, according to both consumer surveys and my personal experience.

Finally, the car is very comfortable on long trips, with a smooth and balanced ride and quiet cabin - I have had to make several 2,000 mile trips over the last year, and always arrive fresh and relaxed.

A bonus is the large amount of headroom, the reason I bought the car, and what I think is an attractive cabin with nice materials - YMMV, of course.

The only thing you may not find acceptable is the handling. The Genesis is not a sports sedan, but more of a GT car, tuned for comfort. The ride is not floaty and disconnected, but compared to the Maxima and 328 you have owned in the past, or the Mazda 6 you recently drove, you will find it less responsive when pushed hard. You will need to do a test drive to see for yourself if the handling balance is what you want in a car.

I am not sure what kind of work or where in NJ you are driving, but when i lived out there i was a road warrior for an IT company and drove 100k miles a year.. the one thing i learned in that time was to buy cheap Toyota minivans and use them to commute.. and have a really nice car for the weekends or nice weather drives.. I purchased a previa altrac i owned for 6 years topping out at 965k trouble free miles, paid 1200 bucks for it.. and had a new Roush 429R jack black edition mustang for the weekends.. Ended up getting rearended and insurance paid 1100.00 for it.. which i used toward a 3000 dollar sienna with 325k miles on it.. and had that to 689k miles when i moved out of there.. Honestly spending 25k every 2 years sucks when you can have something really nice for a longer period of time, and drive something you can sit in traffic in, drive in the snow, or park in lots and not worry about getting dinged.. I suggest minivan because they are typically very wrll maintained.. because frankly who wants there kids in something dangerous..

Just purchased a 2011 Acura TL SH-AWD, and I'm loving it. (305hp J37A4 V6)
Probably a little smaller than the Genesis, but I think it fits your requirements.
Worth considering, but make sure any candidates for purchase don't consume oil

My response is late, but maybe helpful to someone in the future.

I currently lease a 2015 Genesis 3.8 RWD, and I would not recommend this car as a commuter car based on the terrible gas mileage (19 mpg, mostly highway miles) and the lack of performance.

The car weights as much as a whale, and the transmission is programmed to mask the weight penalty - there is nothing even remotely sporty about the way it works, even in "Sport" mode. It's programmed to get gas mileage, and I have found myself wanting for power on numerous occasions. This car has 311 HP, but feels a lot more sluggish than a 2010 Passat I owned, which was a 2.0 turbo four cylinder with FWD. I also have several reliability issues that have been acknowledged by three different Hyundai dealers, with 8 attempts to fix these issues ? over 8 weeks in different shops ? and no resolution on any of them. This is the worst car I have driven, short of the Nissan Versa I got as a rental car from Hyundai while they spent 10 days trying to fix an issue (unsuccessfully I should add).