Bicycle Mechanics - Bike Building Advice Needed (Ultegra 10sp set)

So I'm building a bike with a Trek 1000 frame, cassette, calipers, wheels, and seat post that I got from a friend for free and I've come across a new 10 sp Ultegra 6600 bike kit for $340. The problem is, I've already purchased some 9 sp Sora derailleurs (used) for $25. Is it worth splurging on the set or to continue buying parts separately?

Sora 9 speed derailleur used for $25 = ripoff. Anyways - what components are included in this ultegra 6600 kit?

You may want to price it out against this: http://www.probikekit.com/display.php?code=D1090 It's almost 100% guaranteed you will spend much more buying parts individually, unless you're scouring ebay/craigslist for deals than if you bought the whole groupset together.

yeah i was hoping i'd be able to find MOST of the stuff on craigslist but i'm having a pretty hard time finding a crankset.

<img src=http://i6.ebayimg.com/06/i/000/a6/76/b68f_1_b.JPG>

my concern with doing this is that i already have a bunch of these parts...but then again i got most of them for free...

Sounds like you're already ahead of the curve cost wise. If the equipment you have now is in good shape, and you are a newcomer to road cycling/racing....stick with what you have. It won't ride any less fast than with the Ultegra group. It's the rider that counts, you are the engine.
I've seen some Dura-Aced, Campy-ed, carbon-ed wienies who can't keep up with a 45 y.o. grandmother up a climb!
:D
If its something that you can't live without, then buy the Ultegra kit. But it sounds like you are only a crank/BB away from riding.

crank/bb and shifters as well...

yeah i could really care less right now whether or not its ultegra or sora or whatever, i just want to build this bike as easily and costeffective as possible

The only 10 speed specific stuff you need is brifters, chain and cassette. Can anyone confirm if a 9 speed/crankset/chainrings will work on a 10 speed chain?