When I went on my hunt, I quickly learned that the lower lever models get less of a % off.
I ordered a 2016 JK Sport, manual, AC and premium soft top only and ended up right at 2-2.5% below invoice. Which was good (tho I readily admit not the best ever). It was $25,100 + TTL.
Once you get to the Willy, you can do a little better % wise. And getting to the Sarah and Rubicon, will get even better % wise.
BTW I also got White. Good color. I would seriously consider the premium soft top at order. Especially if your not getting a hard top. They give you a good amount of "credit" for the base soft top. I think a $500 upgrade. The premium soft top on its own is like $1,500.
I did not go Sport S as I really didn't like those wheels/tires any more than those on the Sport and knew I would want to replace them. Would like the leather warped steering wheel, but not a deal breaker.
While I would have liked remote locks (I'm looking to add to mine) I didn't care about power windows. Especially in the 2-door.
I literally only added AC and Premium Soft top, and overall very pleased. Already added an after market stereo/speakers/subs (the alpine upgrade is "ok" but not worth the cost or space it takes IMO). Wheels and tires go in April.