I did my Subaru Turbo Conversion for $3800 Aus, engineered & on the road. That was Xmas 2004 & it has done over 162,000klms since. Thats daily driving & track work.
http://www.youtube.com/watch?v=_5KoIWijI84
They do not run hot, if they do, something is wrong with the cooling system.
I used a Holden Camira Radiator layed on an angle in the spare wheel well with another smaller alloy radiator for the intercooler above it.
If u do most of the work yourself u can save a fortune. there have been conversions in Australia that have run into the tens of thousands of dollars! all well & good if u have an open cheque book.
Hope this helps
regards
Jak