Its going to be big money having the engine out to do a low compression rebuild, We are talking diffrent pistons, diffrent rods, stronger oil pump, you need to fit the oil feed and return to the turbo, stronger head gasket... Then your ECU and engine management system needs changing or remaping.
The average engine build we do is £2000+ And we have a fair few people have done at home which have run the first 100 mile and either blown to pieces or rattling like crazy! its a big job and without all the tools you need they tend to skip important parts of the rebuild.
Realisticly the only way you will get a good turbocharged engine which you can live with and not constantly have to worry about blowing, is dropping somthing like a 1.8T lump or having it all professionaly built up.
Our garage would do it for arround £5000 for a good turbo kit and arround the same for a supercharger, mabey a little less. engine conversions arnt all that much cheeper but always a much better option.
Hope that helps.
