The torque peak is the most effecient operating point in the power curve. It only has one point because the cam is only one point. The manifolds, head and timing are layed out to maximize this one point for all drivers.
VVTi eliminates that restriction. The cam can be varied to fit any need. But yet, you need tuning to dial it in. Whoever said it was a restriction should stop posting about it until you know something about it. And yes, it is the same basic thing as Honda. Not all Honda V-tec equiped motors have variable lift and timing, some are just variable timing. The same as Toyota, which has VVTi and VVTi-L for variable lift.
It is a much better way. For one thing, it eliminates the need for an EGR valve, because you can purge the cylinder at idle, lowering NOx. You could do it with a great big lumpy cam, but then you have HC's spitting out the exhaust.
Finding a way to retrofit VVTi and controll it would be one of the best things you could do to your car. And the IS300 dropping engine weight to get higher fuel mileage has nothing to do with the merits of VVTi.