It will be interesting to see how it sounds and goes one day, but time is very limited. I only used to take the Renault 11 to Santa Pod and Avon Park, but that was a long time ago now. I remember I fitted the turbo gear set into a Renault GTX gearbox to increase final drive as I was hitting the Rev limiter in 4th just before the line. Renault 11 Turbos only had a 6200 limit.

The standard manifold has small runners so the exhaust pulses will be moving much faster than in a tubular manifold. It is interesting what you say though, I would expect spool to be better with the standard manifold, but possibly restrictive for outright power. I had to make a manifold in my case as the turbo was in completely the wrong place. I have put a couple of pictures in my profile to show what it looks like.

When the engine was pushed to the limit I burned a hole through the head gasket and another time cracked a liner in number 4 cylinder due to detonation. I know some people used to make a water connection to the other side of the head, on the existing banking plate, to remove the hot water which causes the problem.

Will be interested to see your progress, the power outputs and 1/4 mile times are way ahead of anything anyone managed in the 90's. Quite incredible for such a small old motor.