Don't you need a different cat for the HF/VX manifold? I thought they're placed in the engine bay compared to under the car for the standard header setup.
You're right. On the HF/VX/HX/STD the cat is directly under the exhaust manifold. On the DX/LX/EX/SI the cat is closer to under the engine. HOPEFULLY the cat+downpipe from the VX/HF will bolt right up to where the old cat/downpipe use to be. If it doesn't custom piping will be required.
Well, my testing of this swap was plagued by alternator failure so I said screw it, have had the vx exhaust on for a bit and it seems to warm up more quickly/get higher cruising numbers, but that's just bs, no serious testing has taken place. Will be putting the cx head on this week so Iono if I'll be testing anything unless someone finds me something to.