Well, take how many hours a seti-wu will take, multiply with 10, and you have a rough estimate of how many days a CPDN-wu will take on the computer...
CPDN-wu is very long, from 3 weeks and up is normal, takes 650 MB disk-space, and has a reputation to crash on many "stable" overclocked computers... and some non-overclocked.
Initial wu-download is large, around 10 MB, and result-size is around 5 MB. Still, due to the very long crunch-times, this is an excellent project even for dial-up. Also a good backup-project for all other BOINC-projects, since nearly 1 years deadline.
BTW, the current model is the small & fast model, the next released should be the sulphur-cycle-model, with expected crunch-times from 2 months...