How about going for the samsung pro ssd ? http://www.overclockers.co.uk/showproduct.php?prodid=HD-159-SA&groupid=701&catid=2104&subcat=2394
Get rid of those fans! haha no but seriously, I had some and they were flimsy, loud and brittle. Also I'd upgrade the GPU, especially as you've gone for a 3770k, if not, you don't need the 3770k for the 660
Does this offer a significant upgrade?
It's not an option on the pre built system unfortunately.
they have done custom system builds for people in the past but you have to phone them up so you likely don't even need to use the system builder presets at all if you don't want toIf you give overclockers a call im sure they will accommodate the ssd of your choice.