you can get the studs from the dealer - part no. 90065-PG6-000 - about $3 each
what downpipe do you have? - the DOHC ZC uses a downpipe like the 92-95 Civic EX (4-2-1) - that downpipe use 2 donut type gaskets between the exhaust manifold and the downpipe, also available at the dealer, part number 18212-SB2-961