Ive been through a DIY job which turned out OK on a 300sd ,I used the original core support and bent it back into shape,if to do it over I would of put a pipe under the metal on the upper core to keep its shape ,it now has a obvious look of repair after ratcheting with a strap and hammering the placement ,the bottom of the support is not damaged but to FIX the top a junkyard salvage piece will be in its place soon.This will be my plan of attacking the core support . Once youve got the cut one off from the yard take a carefull measurement from these two points at the inner fender support at the cut location ,youll want it to be the same measurement on yours ,also when test fitting the piece tack weld and test the hood striker for alignment ,much easier to get it in the zone this way than play with it latter.A welder if everything is laid out for him with which cuts to make and parts on hand already cleaned and ready to weld on would be no more than $250 to do the job.Some will even come to you .Let them do the cut off the car ,they may need some extra length to build from and good luck with that car ,its still in great shape.