Might be worth looking at the refurbished Mac Pro's at the online Apple Store. They come with a full warranty and you can really save some $$'s. I picked one up last year and am very pleased with it. I've used Mac's for about 20 years now & can say it was no different from buying a new non-refurb model.
I just color corrected a wedding invitation for a couple on my new iMac 24" and when I got it back it had a green cast to it even though it looked great on my screen. I used a EyeOne Display 2 to calibrate it. Can I send the file to anyone with good color monitors to check my file or see if it was the printer?