I'll share my story with this forum on trading to a diesel. I understand this thread is old, but maybe it will help others with a real world example.
In February 2013 we purchased a 13 V8 Overland and since the 2014's were already on the lot they discounted it a lot, plus there were incentives from Jeep. In all the 2013 had a sticker of $47k and we paid $38k. I remember thinking that I would really like the diesel, however at the time they were not available. My wife mentioned earlier this year that she would really like the advance safety tech package, that has adaptive cruise, blind spot warning, and forward collision. I also liked the advancements the 2014 had, mainly the 8.4 headunit so we contacted our dealer to inquire about 2014s. They had a Summit V8 on the lot with a discount of $6.8k, bringing it down from $55k to $48k. We went in to have a look. The dealer offered us $34,500 for our 2013 with only 7k miles on it. In all not a bad offer, only $4k under what we paid. Of note, the price I paid back in 2013 was offset by the Jeep incentives (4.5k), so the dealer sold me the 2013 at 42.5k the rest of the discount was from Jeep. So the trade offer was correctly noted above, (about $8k under the original dealer cost). My Jeep was in outstanding condition as well, not dings, stains, etc.
After looking at the V8 they made me an offer on a diesel Summit which I mentioned I liked. It was invoice price, $54k. My dealer claims they hadn't sold a diesel at that much of a discount before, but since I was a prior customer, yada yada. I'm sure I could have easily worked the internet and phones to get a better price on a 14 diesel, but invoice sounded fair, plus the trade offer was also fair.
So, in total the diesel upgrade was $20k! Yup, there you have it. Granted I stepped up from an Overland to a Summit, which was certainly some of the cost. Things like this will make a financial planner cringe, but autos are my addiction and I've never made what anyone would call a smart financial decision with cars. They are my passion.
After owning the 14 Summit diesel for a few months I would say the upgrade is worth every penny. The average mpg is 11 better than the V8 and the added features and luxury items are very nice.
Buyers of GC's need to keep in mind that the cost difference between the V8 and diesel is not just in the MSRP, dealers in my area claim that they can't move the V8 models and are therefore discounting them much more, whereas the diesel doesn't get discounted much, nor is it likely to have any Jeep incentives towards the end of the year. In all buyers may find the real world cost between the two to be much more than the MSRP difference.