As I also have Tagora SX I must say that this engine is absolutely GREAT! Brutal power of nearly 170PS and huge torque moment makes this car very very fast. I can't imagine what will happend if they used it for Murena which is cca 300kg lighter - it had to be a monster. This engine is that brutal also thanks to 2 triple carbs and not by injection (which also calculates ratio between power/consumation/emissions).
But I think that there is not enough space for it and also carbs must be fited longitudaly to work properly, and if you put the engine behind the rear axle, you got the biggest disadvantage of all Alpines - engine at the rear. Maybe it's better than in front of the car, but not better than in the middle - like in the Murena.
Turbo conversions are also very powerfull, but don't want to imagine any problem on the way, to many changes from my point of view. The best and technicaly clearest reason to have nearly 200PS was Murena 4S - with 16 valve technology, but nobody is able to remake this