If you have to ask, you should let someone more knowledgeable do the work. No offense but it's a lot more complicated that what you may think.

 

>eBay turbo
Unknown numbers. Even though it's specifically a t3/t4, every turbo on eBay is kinda different and will put out different different numbers. Just find a decent sized garret or other name brand turbo (that's known to hold up) locally, buy a rebuild kit (if it needs one) and go for it.

As for NVturbo, "it's a lot more complicated that what you may think" is a really strange number seeing he basically only asked for
-a ballpark number in whp (idk 300?)
-a ballpark number in price (small loan of a million dollars)
-a ballpark number in money he'd need (the money left from the small loan of a million dollars)

Just give the guy 3 numbers. There's nothing complicated about that. ¯\_(ツ)_/¯

 

Should talk to the tuner about this.

 

With the setup you describe I would say 300-350whp is a reasonable goal. At that point I believe the Y8 will start to run out of steam without some head work, single cams are limited. But this also keeps you within a safe range for what a stock transmission, axles, etc. will be able to handle without immediate failure.

You will need $ for engine management, fuel system upgrades, clutch, and any components not already included in your ebay turbo kit. For cost of installation, its free, because you need to be able to do this work yourself. If you can't work on it and fix it yourself, then it's not worth owning a turbo car, especially using the cheap parts you've listed that are going to have problems.