Building a HTPC with set-top cable box, how should I configure it?

i have the choice to go with either an IR blaster, or firewire. my cable box is a motorola dcx3200 and I can't find any drivers for it anywhere and im not sure if the signal will be encrypted or not. my other option is using a pci tv tuner, and if i go that route which tuner should i buy that easily allows IR blast setup?