The Good: The car is very good for the price. Great power for a V6, EXCELLENT fuel effeciency and great looks. Very comfortable and comes with lots of features.
The Bad: In most cases you can NOT upgrade to the 8.4 radio. There are a few bugs that sometimes need to be ironed out in the radio (fixed through dealership update) and also many are having problems with the trunk passive entry (myself included) which can also be fixed by the dealership.
I have had my '12 SE for 10,000 miles and almost a year and the only minor issues I have had were fixed by the dealership.
Mods: Mod ideas are endless! My first suggestion for looks would be rims and tint. Next would most likely be a tuner for performance and then performance mods such as 180 t-stat, CAI, exhaust etc.
It's a great car! Good luck if you get it, you will enjoy it I am positive.
2012 SE owner here. No complaints. Rides smooth, very quick, plenty of power for a 6 cylinder and very good highway gas mileage. Sure, I would have loved to have an R/T or even a SXT, but at the end of the day, insurance kept me out of an RT, and I can mod and have the features of the SXT(fogs, 8.4n upgrade, spoiler, back up camera). For the price, it can't be beat. Honestly, I was a college football player, and all my friends either were or still are, and we have no problem sitting 4 6'2+, 220+ pound guys in my car comfortably.
So unless you plan on street racing or going to the track, the 292 hp, 3.6L v6 pentastar engine is plenty of power for your daily driver.
So man, my advice to you is, if you can afford the note+insurance on a RT, then get it(I couldn't lol), but if insurance is going to be a problem for you, there is no shame in having a SE. Trust me when I say you'll love it from day 1.
As far as mods go, ArmyMP stated it best: tint first, then wheels if you can afford it. If not, go for the .75 cent interior mod, plasti dip or color match your grill, black out your tails, change out your interior led lights, go over to the custom exterior/interior lighting dub forum and get you a custom made GOBO puddle light. Holla at Nate from Rebadge design about some custom interior badging over lays. And follow along here, as new and great mod ideas are shown every single day!!