Seen Circoli Thermostats on ECP but never heard of them, do a google search and you'll be scratching your head of where they actually come from which is why I avoided it.
MAHLE on the otherhand is a OE supplier to the VAG group (VW, Audi, Porsche etc.) and ECP do sell them, I had no issues with the MAHLE thermostat I had fitted to my GTI and it's competitively priced with ECP discounts.