u cant flash a 7950 to a 7970 so no
maybe R9 280 non X yah why not same chip after all Tahiti pro
the new R9 280X (not the first batch the new ones are Tahiti XTL which consumes less power than the Tahiti XT) and u cant Xfire a 7970 Tahiti XT with a R9 280X Tahiti XTL But as far as i know all the R9 280 cards are Tahiti Pro and i tried Crossfiring a R9 280 with my 7950 Vapor-x
but seriously why would u even need to flash the card and risk bricking it even without flashing u can pair it up with a R9 280 For crossfire (all hail amd for being nice)
this is for a 150$ after the promo and MIR DAMN CHEAP for another card for Crossfire if you're interested...