Hi
Dumpvalve gives no benifit to the performance or power.
I have never heard of it shortening life of the turbo, have had one on my scoob for 9 years.
The truth is you actually get more turbo chatter without a dumpvalve, but of course you get all the woosh witha dumpvalve.
If yours is still as your picture then i assume you still have the FMIC, Question is does it have the outlet for the dumpvalve? If so its a doddle to fit