The dci 65 already has a turbo (unintercooled though) and runs 1.1 or so bar boost (with spikes it difficult to know) which if you talk to any knowegable petrol head is massive boost. The turbos good for 1.5bar boost accoring to the manurfacturer (KKK) which is huge to put it in prespective the 180hp VAGs run 0.8 bar boost the 225 runs about 1.2bar boost.
Whover said £3k for a turbo I'd run away from quickly they know absolutly nothing.
The engine runs a highish compression ratio of 18.8 which in petrol terms is a supid figure few petrol could ven be made to idel on that level of compression. Diesels are a different kettle of fsih that not that high for diesel the 1.6 VW rabits ran 1.5 bar boost and 23 compression ratio for years no issues.
You can run the car at high boost no need to go internal until you want oer 150hp but obviously the reliability curve drops off the second you start touching the engine.
The engine is idential realy (except for a different turbo, injectors, an intercooler and mapping) from the dci80 the 100 has some modified intenrla bits and the 105 has a stronger block.
Depending what you want leave a message here I'm happy to give you idea but please give me an idea what you want.
A 2.0 172/182 conversion is great value but you loose the mpg and runnng costs of a diesel.