The other nice thing about the vvti is that it eliminates one of the big shortcomings of the 1JZ engine... lack of low end power and torque. If you compare a dyno chart of a stock 1JZ vvti to a non vvti you'll see what I mean. It's a BIG difference. I never compared the 1JZ vvti to a non-vvti 2JZ, but I wonder how close the low end torque figures are.
Based on my own experience, I'd jump at the chance to put a vvti motor in my Supra. My 2.3L turbo Mazda MZR-DISI 4-cylinder in my Mazdaspeed3 absolutely destroys my non-vvti 1JZ at anything below 3,500 RPM (when it had stock turbos, now it kills it up to about 4K). The variable cam timing is mostly to thank, because compression ratio is the same, displacement is less, and car weight is roughly the same, and both car's stock turbos run out of breath around 6,000 rpm.
The only problem with vvti is finding a tuner who knows how to tune it properly. It's not as easy as tuning fuel or ignition maps. It adds alot more time into the tuning process (and expense as a result). Alot of tuners try to ignore it, or try to say it's pointless. It's not, or toyota wouldn't have spent millions developing it. The new HKS V-cam system that you see on pretty much every RB-26 featured in a magazine? Same thing... variable cam timing.
They did make a 2JZ vvti too.
I've heard the vvti rods are weaker, so if your goals include never touching the bottom and and going for huge power you may want to research into that. I've heard random things about vvti rods, but nothing reliable enough to make any sort of solid reference to.
Oh, and it doesn't just help low end power, it pretty much helps power everywhere. It allows the engine to have the perfect cam timing for every situation, instead of forcing the cam profile to be compromised to be "good" for most situations as it is on a fixed cam timing system.
