So, my system is now coming up to 4 years - credit to the Scan build team in that after an early hiccup it has since run flawlessly

My question is whether my system could take a new graphics card (e.g. a GTX980) - in terms of power supply, CPU binding (I think my 2500k can still handle things?) and also physical space.
Given the cramped nature of this case, and my proximity to Scan's store in Bolton, do you also offer a fitting service for upgrades? If so, is it 'while you wait', or do you need 24/48hrs for planning + burn in? If not - then any advice on the above questions would be really appreciated.

Many thanks,