H1 rules:
9.3.1.C "Intake Manifolds are not considered part of the cylinder head and must be unmodified OEM Honda parts. Port matching is allowed but cannot be machined beyond one (1) inch into the intake manifold."
9.3.1.D "Items that attach to the cylinder head may be re-drilled for fitment purposes ONLY. Alteration of air and fuel passages isnot permitted. Fitment modifications that alter air and fuel, as a side effect will be deemed illegal."
H2 rule:
10.3.H "Items (such as throttle bodies and intake manifolds) that attach to the cyclinder head may be re-drilled for fitment purposes ONLY. Alteration of air, fuel, and/or coolant passages is not permitted. Fitment modifications that alter air flow as a side effect will be deemed illegal."

As i read these rules... RBB and RSP TSX/Accord manifolds cant be used with K20 motors in H1 or H2... correct?

 

Modified Honda parts are not a legal part in the series. If you must modify the manifold to fit in any way, You can't use it. You can use a RBB intake on a RAA head in H1 but not H2. You may use the PPA intake manifold on a K24 or a K20 in H2 since it came on both of these motors from factory.

 

right, you can use the RBB or RSP on the RAA head... but you cant use the RAA on a K20 block even in H1. so bascially K20s must use K20 intake manifolds. thanks!

 

correct! No problem

 

Does that mean if you want to run a RBC or RRC manifold you have to run a K20Z3 cylinder head? you can't cut the water neck off to fit the K20A2 stye heads?

 

Correct. If you want to dispute it there is a grey area where is does not say water on the H1 rule like it does in the H2 rule.