If your going with a test pipe, I'm assuming emissions aren't an issue where you live. I put a test pipe on my hybrid for about a week. The exhaust went from deep and loud to fartty and loud and I couldn't take it. Sounded to me like every Neon and Cavailier around here who punches holes in their muffler to sound cool. I put the cat back on and sold the pipe to somebody.

I don't think a CTR header will be overkill (a bad choice of words on my part, sorry) but I though maybe you went hunting for one and paid like $500 for it. Without the insanely high rpm range and breathing capabilities of VTEC cams, your probably not going to push enough exhaust out of that head to really see the benefit of the larger pipes and big collector. Still should work fine, but probably isn't going to really shine above a good smaller/cheaper DC header.

I though about the clearance issues too but didn't post anything. I've heard the B16B was a destroked B18C spec R block, rather than a B16A block with higher comrpession pistons but I've never seen one to really know for sure. If you tested fitted it, I'd like to know the results.

If you don't mind me asking, is your B20 a JDM engine? I have a B18C1 tranny from my hybrid left from parting my motor out and I've been thinking of buying a USDM B20Z (or at least trying to find one) and putting it into my '98 Civic EX. I don't really want to have to convert back to OBD I and use a JDM engine but I haven't had much look finding USDM B20's. I may just say piss on it and and buy an adaptor harness but probably not till after winter (I don't have a heated garage).