Thanks for writing to us.
Dell didn't try the same.
Though we see there are different part#'s for both memory and graphics card for both models, our best suggestion is not to risk.
Also let us know if you wish to know the memory or the graphics card part#'s for Inspiron.
Short cards less than 8.5 inches work fine.
I wasn't able to find ANY GTX 980's that would PHYSICALLY FIT into the case.
Stock power supply will need to be replaced with corsair CS750M or equivalent