As long as you have a green or a yellow spring I wouldn't bother changing it, be a waste of a fiver...
I've got a green spring and though I did try the yellow I found that my car ran better on the original green, some people seem to get given a yellow spring in there dv and some a green, seems completely random. Amd were the orginal company who put mine on with the map and obviously didn't see an issue with the green, when I spoke to Jabba in the past about perhaps changing it to a yellow they said to leave it be, will be fine as it is...
That's comming from 2 well known tuning companies so all this " I get extra boost with this spring" is a load of ***** to be honest, all it does is open and close the diverter...