If the frames are the same size, you might just get the same size and rise steam as what you have on the '03 and use that. From the pictures it looks like it would put you in about the same position on the '07 as you have on the '03-if that is what you're wanting to do. You can also adjust the stem up and down on the steerer tube to get it exact. If it's a Bontrager stem on the '03, you should able to look on the stem and get the specs-length and rise. Also it's hard to tell from the pics, but you might need some more spacers on the steerer tube-if the new clamp on the new stem is shorter than the one you have on the '07. Again you can measure the one you have on the '03 and see how much difference it is from what is on the '07. Hope this helps.

Just from looking at the pics-it doesn't look like there is any extra length of cable housing coming out of the shifters-so if you go much longer either you'll need to slide the shifter back towards the bars or get longer housing. And it's best to cut the housing and cable with the right tools........just makes it easier to work with. I'm guessing you're not going to have to mess with the cable housing though.