I've used DEI heatwrap on my car's 3" down pipe, only lasts about 6 months and then crumbles away.. I've tried copper wrap, graphite black wrap, normal colored wrap.. always the same result.
When you fit it be careful as the dam stuff itches like made if you get the fibers on your skin, wear a mask too.
The wrap would probably last longer if it's coated with the special silicone sealer that's sold separately but they never could post it. The wrap is also easily damaged/abraded and is quite expensive to buy seeing as it does basically fuk all.
Even with the wrap fitted onto my car's down pipe the heat generated was still way too much, even on low turbo boost.