I agree, you don't want to go backwards to the push rod 1.4 turbo charged (garrett t2 turbo) which is a reverse step IMO. I have owned R5 GTTs for over 16 years and they break frequently. The more you mod them the more they break.
If you are serious about a turbo then go for the K-Tec turbo conversion which will set you back mucho dollar! £6K plus is alot of dollar$
You would spend more money keepiing the 1.4 GTT engine running than having the K-Tec conversion jobbie. TherE are all sorts of pitfalls with the Clio/ GTT conversions. What about the emissions laws, the rules on cats etc.. wiring looms are different and on and on...
Still the decision is yours.