Hola.
Cast iron HKS manifolds are great for 400-450 RWHP applications and you don't have to worry about cracking issues. The T2 cast iron manifolds have creep issues if the turbine housing is small. Also the pattern maker of the 2g hks manifold didn't account for casting shrinkage and the ports don't line up with the engine ports. If the 2g is port matched, you are good if you run a .96 A/r T4 turbine housing. The .81 undivided will creep a bit. The FD HKS cast is fully devided and the 1.00 a/r divided turbine housing is about the best combo. With the right external gate, creep will not be seen. The china manifold is fine, not great on quality, but if it cracks, it only costs 100 bucks to replace it
. The china manifold is a better design than the HKS units, but do you want to replace it at a later date? If you don't mind working on your car and you are on a budget, go for the china. You will have to alter a few things, but it should be somewhat close. HKS units are great for 450 RW or less, and if you like to build a car and not worry about it, they are the best for the money. My FB made 440 RWHP on a FD HKS manifold, and I made 435 RWHP with the same manifold with a 62-1 turbo on my FD. If you want 450 or more, you need longer runners, go china
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Bryan@BNR