Er zijn diverse mensen bezig met het tunen van auto's

hier staat nog wel een leuk artikeltje  over turbo manifolds

oftewel  spruitstuk..

http://autospeed.com/cms/A_2604/article....

If you fit a turbo to a naturally aspirated engine, or decide to upgrade a turbo to the extent that it no longer fits the standard manifold, you’ll need to make a new manifold. But if you’re on a budget, how do you go about achieving that? Workshops charge an arm and a leg for custom manifolds, but if you can use a few power tools and can access the services of a welder, it’s not hard to do it yourself.