Originally Posted by Aj
The JDM DC 4-1 and the 98 Spec JDM 4-1 are virtually identical, the DC piece is basically a copy. The nice thing about the OEM header, is that you can add the heat shields, other than that, I'd probably, just on price and weight, go with the DC piece. But either way, you're gonna need the flange, the collector end of both are a 2.5 inch diameter, so you'll also need a special donut gasket, sometimes included.
Later,
Aj
TO add to that DC has the lower setion of the primaries designed a little differently and the one problem I would see if gound clearence. Beyond that they make close to the exact same power and the DC is slightly lighter with even the OEM JDM piece being 9 lbs lighter than stock.