Hi all, I've hunted through posts and found references to "shunting" and faulty valves, but not an exact description of the problem I have. If the problem is covered somewhere then apologies in advance:

I bought the car, a 2008 GT Sport 6 speed manual with 52,000kms, just over a week ago so it's still under full Dealer warranty for 3 months. Under normal acceleration it shudders quite badly as it switches between supercharger and turbo (boost gauge drops then climbs again, assume this is the point turbo cuts in). This may be normal having never driven one of these new. You feel the change in the form of massive power loss for half a second or so and the exhaust note and engine noise disappear then return as the turbo kicks in.
The next problem is that there are points while driving (usually when car is warm) that it feels like neither the S/C or Turbo are working and acceleration is almost non-existent. This might last 1minute, then it goes back to being normal (with the rough change between S/C and Turbo while accelerating) no particular point in time, tonight it was in 3rd gear while I was in traffic, other times it's happened on the highway in 5th or 6th when I've accelerated to increase speed.

Like I said, I bought the car a week ago, have driven it for 1500kms and know very little about the engine. Before this I had a v5 Bora. Some help would be appreciated.