You would have to take apart the case to see if there is room or not. I would guess the drive is standard but the trim around the opening is Dell.
The main problem with external is problems getting full speed burns above 12X but if you get a Plumax case from Dealsonic they have Prolific chipsets that will get to 16X. Also be aware that some people have reported that the front USB connections on their 270s have not been USB2 so you should plug it in the back.
I have a lot of external drives connected and they generally work just fine.