Does it really help?

 

i have it one my header, and yes it does help a lot. when i pop my hood after i've been driving there is no heat near the intake filter/pipe/manifold. all the heat is concentrated near the header. i haven't had it for too long (about 10k miles of city driving) so i can't really say if it causes cracks on your header. oh ya, and this is on a crappy ebay header. NO FLAMING FOR A CHEAP EBAY REPLACEMENT HEADER!!!