Waiting seems the same as trying to time the stock market, which I've never been able to do. A couple thoughts:
If you wait, it might cost
more, plus you will have spent more time without the car you're wanting; ie the double whammy I mentioned earlier.
If you buy now, and then prices fall you can say, Oh well at least I've had my car this whole time. (plus the value will probably increase again later anyway)
I think I'd suggest waiting only if you're willing to
never buy a GT. (or if you're better at timing markets than me ... but you're here asking, soooo
)
Good luck, either way!