That's one of the things I don't like about the front and all wheel drive models. Watching the vacuum/boost gauge on earlier models really gives you an idea of what the engine is doing while accelerating, cruising, hill climbing etc. Volvo didn't want you to consider the turbo something as separate from the rest of the drivetrain and so eliminated the gauge. I miss it in the 2002 S40 we have now.
As for the cool down period--it was totally needed with the earlier non-water cooled turbos and we just got used to the wait--even with later RWD versions, and I continue do that with the S40. -- Dave