Okay, I don't see why you would have to put your stock intake manifold on for any kit. This link has guys with skunk2 IMs running direct port kits as well as plate kits.
https://www.honda-acura.net/forums/s...ntake+manifold

I was pretty sure Zex doesn't make a wet kit, go to there website, it explains the install. I believe they put the NO2 by the throttle body so it can mix with the incoming air as opposed to a wet kit which mixes with the fuel from your injectors. I searched there site as far as teg applications go and only found 1 kit which I believe is a dry kit. But maybe you should give them a call

From the Zex website: Unique design provides perfect atomization of nitrous with intake air supply

also from their website: Do I need to upgrade my fuel kit to use your kit?

Our kit was designed and tested for use with stock fuel kits. It will perform properly on stock and mildly modified engines, i.e. header, K&N filter, exhaust, etc. If major modifications have been performed, i.e. camshafts, heads, porting work, [/b]intake manifolds, [b]etc. It is strongly recommended that a fuel pump and injector upgrade be performed on your engine before using your ZEX nitrous kit.

Also the nitrous kits from NOS aren't really that much more then zex, maybe $20-120 more

As far as nitrous express goes I've heard good things and they have a couple kits, you should check it out.