Should be no issue with thermals. Not sure about driver. L1 format, so it should be 73mm head diameter. Drop in is a bit different from the Trustfire one.
The drop in looks near identical apart from the spring and the little extra after the thread.
Id like to see the real lumen rating.
i like the TF much more. haven't owned a sky ray yet. wonder why with a nickname like fry ray 
ultrafire one there, too. looks just like the TF to me.
That spring is ridiculous and looks more like an after thought or they used whatever they had around. It looks as if it'll deform very quickly and cause problems. The Trustfire version looks more robust and far more reliable.