the turbo damper is nothing to do with power - it's to do with vibration of the manifold. if you use a 2wd manifold, you must use a damper of some sort.

you have 2 options:

1) there is a fancy damper from one of the makers of shiny bits (could be spec R) that has a tripod looking thing that bolts on to the top of the rocker cover.

2) mike rainbird sells a bracket to bolt on to 4x4 head sto allow the use of a std damper. see this thread:

https://passionford.com/forum/viewtopic.php?t=88205

i will be going for option 2, as my project car has nowhere for the damper to fit to (i'm not sure if it's a 4x4 head, or if some twat just cut it off).