VTEC vs VVTI

Can somebody technically explain to me how the valves are constantly adjusting on the Celicas? I completely understand how a larger cam lobe connects to a floating rod to bring up the two valves higher and longer on a dohc Honda vtec engine like mine. I want to learn more about vvti because it sounds more efficient to adjust the air/fuel across the entire power band than kick from low to high around 5k-6k rpms like vtec. Does vvti allow high redlines like Hondas? I mean my engine redlines at 8400 with vtec, and Si engines go to 8,200. What is the GTS's redline?