You need/should keep the tank-like 400E AND get the Corrado (if you can swing it). Both were/are hand-made (coach-built) cars and should provide many years of driving pleasure.
You miss the solid 400E if you sell it...that is a given...and whomever you take in the back seats of the Corrado will hate you...but will be impressed if you take them in the 400E.
Just my 2 cents since my name is James too and I have the MB and Karmann VW as well !!

Look what I can do in my old 16V VW.