First I must say I wish you were closer to This part of the world, I would like to meet you and use your shop for Alfa work. You seem to have Alfas down pat.
Now onto Alfa prices. I also see many Alfa prices going sky high and it reminds me very much of the great Ferrari Frenzy of the late 1980s. I think this maybe speculators who think that they can make a buck buying Alfas now and selling as the frenzy gains altitude. The more collectible cars are the first that are bought up. a safe assumption seems to be that compeition cars are the most collectible. Speculators always the strecth things and will try to sell all GTAs as "the race cars". Ferraris with comp names were sold as comp cars wether they had history or not. Interesting thing is most of that value did not scrub off. A Short Wheelbase 250 GT (the factory raced some of these) which was raced in its time, is worth a ton today. One that was not raced is worth 8 tenths of a ton. A 250 GT (non Short Wheelbase) coupe is ten percent of 8 tenths of a ton.
The frenzy raised the prices of almost all Ferraris. Many have come back down but not to pre craziness levels. The really bad part of the Ferrari frenzy is that the comp cars are no longer within reach of the guys like you and me - the true Alfisti or Tifosi and most of the people who now have the really cool Ferraris don't use them. There are exceptions re the use thing, it seems like you must own at least 5 rental strip malls to buy a comp Ferrari these days.
Hang on to 6C2500s, 1900s, Giuliettas, Giulia open cars, and of course any competition Alfa. If the craziness comes, it will be worth a lot more than selling it now. If you are not inclined to profiting from ths car, if you sell it now be ready to not be able to ever afford it again.