The CD drive is not necessary. You can replace it with a HDD / SSD with an adapter.
Yo uso Carbon Copy Cloner. I use Carbon Copy Cloner.
Si, yo lo hice y la diferencia es abismal. Necesitaras un adaptador y por supuesto el SSD. Yes, I did it and the difference is abysmal. You will need an adapter and of course the SSD.
Shorting the battery is very dangerous. Leave the computer on until it shuts down on its own.
Something about the intel core i7 model with 16 Gb of ram?