I would definitely go with the Grape, there is no doubt that you will be able to find one from the many retailers/ BalNY that will get them in, if you miss it then you will be searching for two hard to come by bags in the future. IF an 04 Lilac shows up later, you may have the funds to buy it then and sell the Grape if it doesn't float your boat.
Also, you get to break it in and have a brand new bag, there is something luscious about a new bag : )
I wish you well,
Bridget