(1) I have replaced the DVD-RW drive in both a Toshibia A205 and a A305 with a Blu-ray rom/DVD-RW drive. It was very easy, not positive about your specific model.
On both of mine it was simply removing on screw on the back. Located about 5->6 inches from the side in-line with the drive. The A205 was visible on the back, but for the A305 I had to open the memory compartment (They "hid" it). The only other thing is the face plate. You may need to use the face plate (they pop off easily). For the A305 I bought a sony Blu-ray drive and the face plate from the old drive did not fit the Sony drive. So modified the sony face plate (had to cut a small notch out).