That's actually an E-six, not an E6! In fact, a 2001 E-six. The previous model was called the E4, the subsequent model was called the E8, but that is an E-six, don't ask me why.
It's made of Easton Elite, and it was made in 2001 and 2002. It's similar to the E4 (1998-2000), except that it has disc tabs. The catalogue says it was sold with a Manitou Mars, but I can't quite see if that's what you've got there.
Unfortunately, the Orange catalogues in the Retrobike archive only go up to 2000 (this is Retrobike after all). There is a copy of the 2001 catalogue on the Orange website if you're interested, but I seem to recall it isn't easy to find. Failing that, I could send you a copy if you want. PM me your email.
The E models were Orange's top of the range XC race bikes BITD, made in small numbers, I think 200 per annum at that point, including frame-only sales (the frame used to cost £550).
If you do a search for 'citrus fruit', you will find a good thread and I suggest you add your bike to it. I'm not quite sure, but it might be the first E-six in there if you did.