Nothing changed on the 17 vs the 16.
I sometimes wish I got the Premium, but with a 4k difference in price new, it's very rarely.
Mine is a 15 GT base with Performance Pack and rear sensors, MSRP $35,990. I got it for $31,750 and 0% financing in August 15.
You're a few months later in a similar situation, so I'd expect 4-5k off MSRP.
The 20s look good, but fuck are they heavy.
I'd not get one without the PP, but thats a personal preference.
Good luck.