The effectiveness of the Turbo charger wasn't really the question you raised, it was the possibility of it being installable or not was.
Yes, a CD70 or a 125 can be turbo charged
Will it be effective enough? It won't be fully effective indeed but there certainly will be a boost present.
As for your disbelief of the Deluxe not reaching 160kmph, to each his own. All i can simply do is share my personal experiences. If you notice my emphasis in my previous post was never on weight reduction only, It was mostly on the heavy engine modifications that will be needed to achieve the speed which you consider is impossible.
Approximately 2 years back from now there was this friend who used to love racing, with very few and slightly effective modifications on his '94 125 he was able to race out every 125 and end up on the winning side, however, the days of his being happy about winning were short numbered as a friend of his bought a RX115 and started to kick the living bejesus out of his 125, and why not, the rx115 did 150kmph while the 125 did 115-120kmph. He asked what he needs to do to win against the RX115, I answered by simply getting a RX115, he said I love my 125 and want to outrun it with it only, I said there will be heavy engine modifications to achieve that, to which he agreed upon without any hesitancy.
Here are the list of mods that I did on his engine, I wish only increasing the cylinder size helped us achieve the speed he needed as you mentioned, but that just isn't how it is on a 4 stroke.
Connecting rod stroked
Bored Engine Block
Bored a 180cc Piston (Boring the Cylinder to accept it is relatively hard but not impossible)
and lots of other minor modifications, i.e: sprockets, Ignition timing moded, oil cooler added, weight reduced, added a star/hero front disc brake setup on it too.
The outcome: It ended up doing 165-170kmph with relative ease and was able to outrun the Rx115 in pretty much every race that involved a long run.