I wouldn't do an engine flush if I were you, heard from many sources (general car parts places right up to tuning companies) that it's a very dangerous thing to do, especially with turbo charged engines. You're far better off changing the oil, doing just 1000 miles then changing it again to flush the engine but in all honesty it's really not worth it. Just stick to 10,000 mile services, or 5000 miles if you want an extra clean engine.