i have a toshiba sd-r1002 dvd/cd-rw combo drive. What is the maximum amount of data i could burn onto a imation 80 min. 700mb cd?

If your writer supports overburning:

Probably between 710-725Mb with data.

Why not do a test with the overburn test in Nero CD-Speed? Grab it here: www.cdspeed2000.com