thanks votinh and Cyril for the quick response.
the SD card i was referring to was the external SD. i don't plan on installing too many roms but will make sure to do a complete wipe prior to any install.
was this process of installing ExynosAbuse-v1.40 exploit, install Mobile Odin Lite, SiyahKernel v2.6.14, ClockworkMod Recovery, to get me to root? and once to root, to install a rom?
another question, kernal and rom updates, are they independent of each other? can i update one without the other?
i understand roms are numerous and customized, what about the kernal? does changing the kernal make any significant changes to the operating system?