Mike is quite right. There is a discussion about a x14xe turbo kit in our motorsection. The actual "result" of that discussion is, that a turbo upgrade of a x14xe is practicable and gives an enormous boost of power. But on the other hand you can get a C20XE for nearly the same price here in germany.
So its up to you wheter you took round about 5000 Euro for the tubro upgrade @ x14xe or nearly the same amount for a motor change to c20xe.
Turbo upgrade actually is a bit more individual than the upgrade to c20xe.
Also the durability of such an upgrade is quite untested.
The c20xe motorchanges are "standard program" in germany. durability and faesibility are almost tested to the end. But on the other hand you do not have a real individual machine...
I think that's all so far
