That's cool! I thought that since they seem similar, they would have the same reflector. Do you have any idea how others compare, like the TR-801, UF2100 etc, which "seem" to be similar in size?
So it's like you say, you change the driver and you have a hell of a little cannon... :)
About brightness, I would say yes and no, conditionally.
V6-T60 hotspot is brighter, but I'd say HD2011 gives more light overall because of the floodier beam pattern and it's direct drive. HD2011 also gets hot *much* faster (on high) than V6-T60, you can feel it heating up within a few seconds. For V6-T60 it takes about a 30s to a minute, give or take.
It also depends for what distance you plan to use them. V6-T60 is a better thrower, for all stated reasons.
I don't really know. I'd say it's not, but I have no really good way to be 100% certain of that. I did measure 2.8A on V6-T60 high with the stock driver, with a cheap DMM, and really lousy probe wires. So my sample (at least) was driven pretty hard.
I have both the UF2100 and the HD2011 and they are nearly identical in construction and output. Beam output is the same as far as spill and hotspot but on the HD2011 spill is silky smooth where the UF2100 is ringy.