I use it with SST20 LED, smooth reflector, 1750 mA driver (12 groups 7135x5). It becomes 43 degrees of Celsius hot externally, 50 C internally. I can use it long time in maximum mode. I tried 2100mA. It became about 50 C externally and 60 C internally. It is uncomfortable hot. Flashlight was in 2m from wall on photos of spot. There are 10cm marks on ruler. Diameter of the brightest part of spot is about 20cm. S8 SST20 1750mA lights little further than S2+ SST40 1500mA. S8 has less side light than S2+ SST20. S8 has much deeper reflector than S2+. Maximal distance of S8 was 80-100 m to see something. 60-70m to see good enough.
Very good quality, great price