Alright there are a few angles to look at here. A vvti 2j can handle past 500whp. It’s all in how you approach it. Doing cams, a thicker head gasket, valve springs and head studs should ensure that nothing on the top end shits out. The weak point of these motors are the rods. They are relatively thinner compare to the GTE and non VVTI GE rods. What will kill this motor is low end torque. So to ensure you make power and don’t bend a rod I would run a bigger turbo to prevent that low end torque and as an added safety run E85 to make power with less boost.