s2s2's are not carb legal. but u never see them, so for visual it doesn't matter, but it will be a little harder to pass emissions.
s2's are a little too much on a b16, especially if the compression is stock.
I'd go...
-s2s1 cams & camgears
-hondata IM gasket
-hondata s300 (& and a visit to a good tuner)
-valvesprings
-have the head milled about .010" to increase compression a bit & if money affords, send it to alaniz or portflow for a mild valve job
forget the IM, its not really going to help on your setup. forget the tb for the same reason. instead use that money on something benefitial. I'd buy better valvesprings. Then pull the head, send it to alaniz or portflow for a mild valve job & a slight mill, they will also install the valve springs while they are at it. Now u will have a better flowing head, a little more compression, and be able to safely rev higher. All that will benefit u much more then a TB & IM.
-im buying a welder personally (with my tax money)
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2000 EBP Si 181.5whp, 119wtq- All Motor B16
1994 EG Hatch
2000 BMW 328ci
207 Forever- RIP