For instant spooling....
Look into a .42/.48 T3 garrett from a dodge turbo car or Volvo. If you want more power, put a 2.3T .60 compressor on it, if you want more power yet, put a .63 or .82 exhaust housing, more power yet, put a T04E compressor on it...... See where im going??? Start small and upgrade, Start with a used T3, buy an ebay rebuild kit for it, and then just upgrade it as you go.
Those would be perfect for instant spool and should get it done till you run out of steam.
Full race engines cost big $$$, start stock and upgrade parts as you break um, thats the best way to go about it.