Was extremely (or at least was supposed to be) extremely straightforward, i simply followed instructions from here.
Please remember to change the distribution name in /etc/apt/source.list from STABLE to SARGE when updating the system the final last time before dist-upgrade and then from SARGE to STABLE when doing dist-upgrade.
Side note: I got the internal bay and placed the new hard drive inside. Works under linux. Timings are: