I kind of think the $4500 sounds high, too, but that's what the order guide is showing for both the 3LZ and 4LT. The main aspects of these two new packages are the available two-tone leather options of ebony/linen or ebony/sienna on the seats, plus the same two-tone leather combination on the instrument panel, door uppers, and console cover. Bear in mind the console cover, dash, intstrument panel and door uppers are still vinyl on the 2LZ and the 3LT. Although it looks nice, I'm not sure all that leather is worth the mark-up. Other options on the 3LZ and 4LT are the same as the 2LZ or 3LT.
Also let your customer know that the leather-wrap option is still not showing as available yet. Probably will be available in about another month or so, though.
The current edition of Car and Driver has a very nice article describing the differences, including a comparison of last year's model. The one thing they made a very big deal about is that the steering has been improved, with much better feedback, allowing the car to be driven fast much more confidently.