Shouldn't cause any problems; the SSD in the Momentus caches reads but does nothing for writes. Will this be an external storage drive or does your laptop have two drive bays?
 
	 
	You are doing it bass ackwards from what I would do. I would put the SSD in the main internal SATA bay, and put the Momentus XT in the optical adapter. (Similar to my Ultrabay.) I would want the main OS/boot drive to be in the #1 priority position. That way, if needed, I could replace the dapter with the optical for a short purpose.
MXT is a gimmick and as storage would perform similar to a non hybrid drive.
For those of you that feel otherwise about the MXT I'll say this: If your usage is very much the same day to day yes it does speed those things up almost like an SSD would. But for those with more dynamic use patterns, the SSD is the only way to go.
vraptor in a laptop? Wow!
Well it is a 2.5" drive lol and was made for a laptop.
Not only too thick, it is housed in a 3.5-in "ice box." LOL

 
				
		