I posted this a little earlier in another post, but just saw this one so i will put it here too.
I think I am able to shed some light on your Avanti Competitor, It was a 2000 model that officially was an Australia only model (even though Avanti was started in NZ). The standard competitor was blue where yours is yellow, and had a mix of XT and XTR, and had a blue Manitou SX from memory. They were a very popular option for XC racers in NZ as they were a very nicely specced bike that was a fair bit more economically priced that overseas options.
The frames were the same Easton Ultra Lite tubing, with different paint schemes. I remember there being a hand full in NZ at 1 point, I put one together for the NZ womens rep at the Sydney Olympics.
They kept with the Easton tubing for a few years after until Carbon took over.