on my 01 prelude i purchased a new muffler for better flow, and of course better sound, the inlet on the new muffler is a tad bit bigger, i was wondering if anyone knew the diameter of the stock exhaust pipe?  

I think that on there it might be around umm 1'6/8 or something around there. this is from the accord.. why don't you get a tape measure and wrap it around the pipe.