I think it has alot to do with the condition of the wheels and housing. Assuming that the shaft isn't so worn that it needs to be replaced, if the wheels and housings aren't scraped, cracked, dented, bent, etc... then you can scribe the compressor wheel, shaft, and nut... then disassemble and install the rebuild kit... then reassemble. That means that you're basically in a brand new b16g for the cost of the turbo plus kit. On the other hand, if the finds are damaged and you have to replace the wheel then you'll also have to pay to have it balanced and you may as well just buy a new turbo.