Why is it that everyone ignores me whenever I try to explain that wrapping the entire downpipe will increase lag? If you're going to wrap it only wrap the portion before the bend to help offset this effect.
In theroy wrapping the downpipe will increase spool time but with a TMIC I think it's a reasonable trade off. I only wrapped the upper part of the downpipe inside the engine compartment to minimize this effect.
You want the hottest possible gasses before the turbo and the coolest possible gases past the turbo in order to promote spool.