I spend that sort of money on a turbo some years ago.
Blew an oil seal, so sent it off for rebuild. it came back nice and shiny, but no matter what I tried, I couldn’t get it to boost properly.
Gave up and took it to a garage; they scratched their heads for a while (at my expense) and finally realised that the refurb place had adjusted the waste gate actuator to hold it ever so slightly open in its rest position – so it was never boosting.
GRR!!!
I’ll stick to bikes, at least you can normally see what is going on, and you are less likely to burn yourself by sticking your hand in there to figure stuff out.
Dave