Anything above 400 hp will require an internal forged rebuild.
You will require to run VPro, VPro loom, upgrade the fuel pump and fuel pipe return and fuel rail set up, injectors, fuel bypass regulator, induction pipes will have to manufactured, air filters, oil cooler, radiator, intercooler, boost controller, extra gauges, wide band commander air fuel ratio monitor, suitable exhaust system, dump valve, uprated clutch.....the list goes on and on....The above is just off the top of my head and in no specific order.....Then brakes and suspension will required sorted.....Mapping £500 +....
If you want to run sub 400 hp then you will get no change from 10K.
If you want to run around a safe 600 hp and 600 lbs ft like me, then you will require 20K+ and that will not be the end to your spending.
Hope this helps, but it really is a mine field with loadsa hidden costs/extras and the decision to go fi should not be taken lightly.
great post taken from ZMANALEX