Was ist ein "Porcupine boiler"? Those fingers in the photo? Does that improve heating?
That turbine looks like a Karsten Gintschel , very well made. I recall Wilesco had one with a plastic turbine housing.
Yes, the little “fingers” and they are attached to a plate with round holes that’s soldered to the bottom of the boiler. This should improve heating, and appears to do a good job of it as I ran mine out in the cold and it held pressure.
The T90 is the plastic turbine and turned me away from buying the T125. It wasn’t until I realized it was a Karsten Gintschel turbine and seen how well they worked that I decided to buy one.