The Saucy Haus

So this guy is selling his 90 TT 300zx for 5k. It has a moderate rebuild on the engine, with new gaskets and rod and main bearings. He has installed a 300 degree fuel rail, 615cc injectors, a wiring harness from a 94 Nissan (don't know which), and a cam timing sensor (to eliminate need for splicing new injection connections into engine harness). The turbos on the car are brand new ball bearing t28s. From my understanding, it will need a new ECU, or can it be run on a reprogrammed stock ECU?

My main question is: Is this a setup capable of handling 500whp? Are there any other supporting mods I would need to do, besides maybe a new ECU from Jim Wolf or other? Are the injectors, fuel rails, etc good enough to handle these power levels? Will the stock intercoolers be able to handle it?

The car has sat for a few years after installation of new parts. He says there is a leak at the fuel rail, and I would need to reinstall it. Is this a very difficult job? I know I will need to also check things like the spark plugs and do a compression test and maybe a few other things.

Open to opinions, advice, etc. New to this platform, though I have a good bit of time wrenching on other cars. Thanks.