Hello, im thinking about ajusting the IP on my w123, but i cant find anything about the powergain with stock pump and stock IP?

Is it worth it?
How much power will i gain?
How much faster will it be? (i know it is 15 sec to 100kmh stock, so i know it's not going to be a race car, but maybe it will be a little faster)

thanks for any reply, and sorry for my bad english