Get it to someone who knows these cars, tell us where abouts your from and we can tell you who's best for you to take it too!

I'd lay off giving it some right foot untill you get the all clear even tho it seems to be ok, as with any rs turbo bought second hand, sometimes you just dont know if it's ok!

He may mean bleed valve rather than power boost valve. . these are ok to have aslong as you dont touch it!

Not sure it sounds like lag, as it shouldnt really have a whole lot (unless you've no experience with turbo's and expect instant power when you put your foot down)