The Conquests come with a Luxfer tank which is extremely light (my 1.1l was a shade under 850g if I remember.) Combined with the fact that the reg itself only weighs an ounce more than your average preset reg it is a vey light system indeed. I did weigh all the bits but didn't write them down; from memory the whole system was about 1050g.
Unfortunately, that bottle is DOT only and the first thing I had to do was swap it for my HSE/DOT tank, which weighs about 930g. However, I think once you allow for the mounting hardware, plus the fact that it runs without an inline, my setup is noticably lighter than before.
Oh, and drifting off-topic I know, but I promised a quick review of the 2k3 Conquest. Executive summary: GET ONE.
I did have a bit of a scare the first time I used it because some teflon tape from something (the gauges are put in with teflon tape!) got in the seat and it started pissing air, but once I'd got that out it was sweet. Damn good flow, very consistent once it's had a couple of thousand shots to settle down, doesn't need an inline reg unless you really feel like it. I'd say it's at least as good as a Max Flo but a hell of a lot lighter and smaller.