Reading around it seems the stainless steel cooling unit by FTV is not very well regarded, so I will try to give a different perspective as I have recently gotten the Crafty to perform in a positive way for the first time after owning it for years.
What I didn't like about the Crafty was that the vapor was harsh and tasted muted with plastic undertones. It would also make me cough very easily (the infamous Bickle tickle), and I didn't find the vapor particularly strong (too diluted).
People can argue all they want about PEEK not off gassing, but some interaction with the terpenes definitely happens and something of the PEEK is present in the vapor otherwise you would not be able to taste it, it's not that complicated to reach this conclusion. Whether this is harmful or not is up for debate, my main concern was the impact on taste.
Good news is that everything that is behind the plastic cooling unit is well thought out in terms of materials used. So basically replacing the cooling unit with a rocket stem or stainless steel CU will greatly improve the taste.
The FTV steel cooling unit is not perfect, it is rough around the edges, it sometimes feels like you could potentially cut yourself on the fins, it is very heavy making the light Crafty much more bulky and top heavy, and you need to be very careful while handling and cleaning it so as to not grind metal on metal and get some dust... But it does it's job and one can finally taste the material properly.
It works much better when the Crafty is used at max temperature. This way you can extract everything from the material before the cooling unit gets hot. Counter intuitively, if I lower the temperature to 180c I feel the cooling unit gets hot before the bowl is spent.
I also started packing the Crafty quite tight, using the packing tool, this gives it more restriction in the pull, and I pull very slow. This gets a more conduction type effect, with thick vapor that is not harsh to the throat because you are sucking in a lot less hot air.
I never enjoyed this vape until now, but using a different cooling unit and different packing technique/draw speed made a huge difference.