From all the information I have on Fw's the Ta-152 was intended to be a modification of the 190 series. The Dora series was an intermediate step to the Ta-152. If Hitler hadn't gotten involved by trying to reward Kurt Tank, it would have had an Fw 190 designation instead of Ta. The plug to lengthen the Ta's fuselage is similar to the plug in the Dora tail, just longer. As to the wing design, it is significantly different, but it was intended to mate to the 190 fuselage in exactly the same manner.
So based on the information I have, It's my opinion that they didn't use the components because they were available. Instead, they used the components because they were tasked with modifying an existing design to create the Dora, and ultimately the Ta-152.
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unless we want to get into the specifics of the orders that were placed to build the aircraft we're discussing, we many want to approach this differently. A different discussion/thread might be in order, something like "How much of an aircraft design can be modified before it should be considered a new design?"
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