VVT-i is nothing like VTEC. VVT-i changes the timing on the engine constantly, giving you fuel economy when you need it, and power when you need it. You're probably thinking of VVTL-i on the GTS. That uses two different camshaft profiles like VTEC to increase high end power, which allows the redline to be increased over the GT without losing power. VVTL-i is actually more advanced than VTEC, since it incorporates variable valve timing along with different cam profiles.
Unless you have a turbo, SC, or nitrous (and probably stiffer valve springs so you don't ram your valves into your pistons), raising the rev limiter on a GT will only lose power fast. Not worth doing, since the GT is already losing power before it gets to the limiter.
The GTS, on the other hand, still makes power at the limiter because of VVTL-i's second cam profile. Raising the limiter would still allow the engine to make decent power, and allow the driver to land in lift on every shift.