for my 85 crx hf, the muffler and pipe came from the dealer as one piece when I orderd a new one, it was a 9 foot long part! exaust pipe, muffler and everything and bolted to a short stub of pipe that comes off the cat, just in front of the oil pan, the 2nd generation crx hf has a two piece muffler and exaust pipe, but I suspect it's still a smaller pipe then the higher horse power modles, and it is also going to be lighter weight, they also come with a life time warenty for as long as you own the car, or so they tell me at the dealer.
http://www.hondaautomotiveparts.com/...EXHAUST+SYSTEM
is the 1988 crx hf exaust parts list.
I would be tempted to get parts that are ment to fit, as then you can easly install them your self, as honda exausts bolt together with flanges and are extreamly easy to work with if they are stock, if they are not stock then you are paying someone else to fabricate parts for you at $50 an hour every time you have a problem.