external writer drive vs internal

I might implement a strange solution to reading and writing cds and blu ray on my notebook. I will buy an LG internal drive like the GGW 20-L and have it running outside, connected to an SATA expresscard, and the power supplied by a Corsair 520W psu. Is the solution viable? The psu seems excessive, however I can use it for another build or do a split. I could buy a USB CD/BLU RAY r/w but if it fails then all is lost. It might be cheaper to buy things separately tbh.