Your kidding me you are even asking... Its definitevely worth it! I have a klein attitude race hanging with some xtr components on it and i plan to re-build it this year. Id love to have a aura as my road bike.
Its definitivly worth any components, even dura-ace, record, or red. Now, which ones depends on your budget, and on your likes. No point in starting a shimano vs campy vs sram discussion here.
I do suggest that you try to get to test ride bikes with the components you plan buying, as the greatest difference between brands (not between different groupos of the same brand)is in the "feel" of the components, not in quality, weight price or anything, and feel is something where only your opinion maters.
Try to post some pictures if you can for us to klein-drool a bit