I've been looking into the 03 as well. The price from WCT is $1375USD. But after ppl brought up there might be a different wiring harness in the '03 model celicas then it might now fit the '02(if that's the case then there's a lot of work involved). But if 00-02 celicas also was provided with the extra wires, maybe we just need an adapter or something.
WCT is still looking into it, but I hope ppl with '03 HIDs can line up side by side with a 00-02 celica and see if 02 provided any extra wiring.