wrapping the uppipe is just as important as wrapping the header. The stock uppipe comes with a heatsheild on it for a reason. When you switch to an aftermarket uppipe they do not come with any kind of heat sheilding. The heat from the turbo system can cause the engine to be more prone to detonation, can dry out gaskets/seals in the cylinder heat, possibly damage the coil packs etc.
If you're going to do it, you should spend the money and do it right. Not to mention, your turbo will spool up faster and you'll make some additional HP.