Headers are really expensive for those engines and are a PITA to install. they probly wouldnt be worth the money.
From everything I've heard, it's quite the contrary. The stock manifolds are super restrictive and poorly designed.
1kz?? its a v6 3.0 in a 94 4runner (3vze) 3" exhaust and a boost controller will not help it! 
He doesn't live in the us and might not realize that we weren't allowed the sweet diesels!
